Branched-chain amino acid supplementation in patients with liver diseases

Deficiency of BCAT2-mediated branched-chain amino acid catabolism promotes colorectal cancer development

OBJECTIVE

Branched-chain amino acid (BCAA) metabolism is involved in the development of colorectal cancer (CRC); however, the underlying mechanism remains unclear. Therefore, this study investigates the role of BCAA metabolism in CRC progression.

METHODS

Dietary BCAA was administered to both azoxymethane-induced and azoxymethane/dextran sodium sulfate-induced CRC mouse models. The expression of genes related to BCAA metabolism was determined using RNA sequencing. Adjacent tissue samples, obtained from 58 patients with CRC, were subjected to quantitative real-time PCR and immunohistochemical analysis. Moreover, the suppressive role of branched-chain aminotransferase 2 (BCAT2) in cell proliferation, apoptosis, and xenograft mouse models was investigated. Alterations in BCAAs and activation of downstream pathways were also assessed using metabolic analysis and western blotting.

RESULTS

High levels of dietary BCAA intake promoted CRC tumorigenesis in chemical-induced CRC and xenograft mouse models. Both the mRNA and protein levels of BCAT2 were decreased in tumor tissues of patients with CRC compared to those in normal tissues. Proliferation assays and xenograft models confirmed the suppressive role of BCAT2 in CRC progression. Furthermore, the accumulation of BCAAs caused by BCAT2 deficiency facilitated the chronic activation of mTORC1, thereby mediating the oncogenic effect of BCAAs.

CONCLUSION

BCAT2 deficiency promotes CRC progression through inhibition of BCAAs metabolism and chronic activation of mTORC1.

Pathophysiological-Based Nutritional Interventions in Cirrhotic Patients with Sarcopenic Obesity: A State-of-the-Art Narrative Review

In recent decades, following the spread of obesity, metabolic dysfunction has come to represent the leading cause of liver disease. The classical clinical presentation of the cirrhotic patient has, therefore, greatly changed, with a dramatic increase in subjects who appear overweight or obese. Due to an obesogenic lifestyle (lack of physical activity and overall malnutrition, with an excess of caloric intake together with a deficit of proteins and micronutrients), these patients frequently develop a complex clinical condition defined as sarcopenic obesity (SO). The interplay between cirrhosis and SO lies in the sharing of multiple pathogenetic mechanisms, including malnutrition/malabsorption, chronic inflammation, hyperammonemia and insulin resistance. The presence of SO worsens the outcome of cirrhotic patients, affecting overall morbidity and mortality. International nutrition and liver diseases societies strongly agree on recommending the use of food as an integral part of the healing process in the comprehensive management of these patients, including a reduction in caloric intake, protein and micronutrient supplementation and sodium restriction. Based on the pathophysiological paths shared by cirrhosis and SO, this narrative review aims to highlight the nutritional interventions currently advocated by international guidelines, as well as to provide hints on the possible role of micronutrients and nutraceuticals in the treatment of this multifaceted clinical condition.

Use of Branched-Chain Amino Acids as a Potential Treatment for Improving Nutrition-Related Outcomes in Advanced Chronic Liver Disease

Advanced chronic liver disease (ACLD) represents a complex and multifactorial clinical entity characterized by liver dysfunction and associated complications. In recent years, the significance of nutritional status in ACLD prognosis has gained considerable attention. This review article delves into the multifactorial pathogenesis of malnutrition in ACLD and its profound consequences for health outcomes. We explore the clinical implications of secondary sarcopenia in ACLD and highlight the critical relevance of frailty in both decompensated and compensated ACLD. A specific focus of this review revolves around branched-chain amino acids (BCAAs) and their pivotal role in managing liver disease. We dissect the intricate relationship between low Fischer's ratio and BCAA metabolism in ACLD, shedding light on the molecular mechanisms involved. Furthermore, we critically evaluate the existing evidence regarding the effects of BCAA supplementation on outcomes in ACLD patients, examining their potential to ameliorate the nutritional deficiencies and associated complications in this population.

The Role of Branched-Chain Amino Acid Supplementation in Combination with Locoregional Treatments for Hepatocellular Carcinoma: Systematic Review and Meta-Analysis

BACKGROUND

Branched-chain amino acid (BCAA) supplementation has been linked with favorable outcomes in patients undergoing surgical or palliative treatments for hepatocellular carcinoma (HCC). To date, there has been no systematic review investigating the value of BCAA supplementation in HCC patients undergoing locoregional therapies.

MATERIALS AND METHODS

A systematic search of the literature was performed across five databases/registries using a detailed search algorithm according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. The search was conducted on March 23, 2022.

RESULTS

Sixteen studies with a total of 1594 patients were analyzed. Most patients were male (64.6%) with a mean age of 68.2 ± 4.1 years, Child-Pugh score A (67.9%) and stage II disease (40.0%). Locoregional therapy consisted of radiofrequency ablation, transarterial chemoembolization or hepatic artery infusion chemotherapy. BCAA supplementation was in the form of BCAA granules or BCAA-enriched nutrient. Most studies reported improved albumin levels, non-protein respiratory quotient and quality of life in the BCAA group. Results pertaining to other outcomes including overall survival, recurrence rate, and Child-Pugh score were variable. Meta-analysis showed significantly higher levels of post-treatment serum albumin in the BCAA group (SMD = 0.54, 95% CI 0.20-0.87) but no significant differences in mortality rate (RR = 0.81, 95% CI: 0.65-1.02) and AST (SMD = -0.13, 95% CI: -0.43-0.18).

CONCLUSION

BCAA supplementation is associated with higher post-treatment albumin levels. There are currently not sufficient data to support additional benefits. Further studies are needed to elucidate their value.

Emerging role for branched-chain amino acids metabolism in fibrosis

Fibrosis is a common pathological feature of organ diseases resulting from excessive production of extracellular matrix, which accounts for significant morbidity and mortality. However, there is currently no effective treatment targeting fibrogenesis. Recently, metabolic alterations are increasingly considered as essential factors underlying fibrogenesis, and especially research on metabolic regulation of amino acids is flourishing. Among them, branched-chain amino acids (BCAAs) are the most abundant essential amino acids, including leucine, isoleucine and valine, which play significant roles in the substance and energy metabolism and their regulation. Dysregulation of BCAAs metabolism has been proven to contribute to numerous diseases. In this review, we summarize the metabolic regulation of fibrosis and the changes in BCAAs metabolism secondary to fibrosis. We also review the effects and mechanisms of the BCAAs intervention, and its therapeutic targeting in hepatic, renal and cardiac fibrosis, with a focus on the fibrosis in liver and associated hepatocellular carcinoma.

Equine placental extract supplement as a night barking remedy in dogs with cognitive dysfunction syndrome

With the aging of pet dogs, there has been an increasing trend in senility‐related diseases; additionally, cognitive disorders accompanied by abnormal behaviours are a major burden for owners. Recently, there have been a series of consultations regarding the fact that night barking, which is an abnormal behaviour, remarkably interferes with the owner's sleep and adversely affects the owner's quality of life. However, there has been no effective solution to this problem. In this study, three aged pet dogs diagnosed with dementia were administered an equine placental extract (eqPE) as pet supplement, which has been shown in laboratory models to improve cognitive function. Consequently, night barking ceased 1 week after the administration of eqPE in case 2 and it was observed to decrease in the other two dogs. Furthermore, night barking disappeared 2 and 3 weeks after the administration of eqPE in cases 1 and 3, respectively. No recurrence or exacerbation of night barking was observed in the three cases treated with the eqPE, and no adverse events were observed. These results suggest that eqPE may be useful for improving night barking in pet dogs with dementia, and it is expected to be a new treatment method.

Hepatic effects of rumen-protected branched-chain amino acids with or without propylene glycol supplementation in dairy cows during early lactation

Essential amino acids (EAA) are critical for multiple physiological processes. Branched-chain amino acid (BCAA) supplementation provides energy substrates, promotes protein synthesis, and stimulates insulin secretion in rodents and humans. Most dairy cows face a protein and energy deficit during the first weeks postpartum and utilize body reserves to counteract this shortage. The objective was to evaluate the effect of rumen-protected BCAA (RP-BCAA; 375 g of 27% l-leucine, 85 g of 48% l-isoleucine, and 91 g of 67% l-valine) with or without oral propylene glycol (PG) administration on markers of liver health status, concentrations of nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) in plasma, and liver triglycerides (TG) during the early postpartum period in dairy cows. Multiparous Holstein cows were enrolled in blocks of 3 and randomly assigned to either the control group or 1 of the 2 treatments from calving until 35 d postpartum. The control group (n = 16) received 200 g of dry molasses per cow/d; the RP-BCAA group (n = 14) received RP-BCAA mixed with 200 g of dry molasses per cow/d; the RP-BCAA plus PG (RP-BCAAPG) group (n = 16) received RP-BCAA mixed with 200 g of dry molasses per cow/d, plus 300 mL of PG, once daily from calving until 7 d in milk (DIM). The RP-BCAA and RP-BCAAGP groups, on average (± standard deviation), were predicted to receive a greater supply of metabolizable protein in the form of l-Leu 27.4 ± 3.5 g/d, l-Ile 15.2 ± 1.8 g/d, and l-Val 24.2 ± 2.4 g/d compared with the control cows. Liver biopsies were collected at d 9 ± 4 prepartum and at 5 ± 1 and 21 ± 1 DIM. Blood was sampled 3 times per week from calving until 21 DIM. Milk yield, dry matter intake, NEFA, BHB, EAA blood concentration, serum chemistry, insulin, glucagon, and liver TG and protein abundance of total and phosphorylated branched-chain ketoacid dehydrogenase E1α (p-BCKDH-E1α) were analyzed using repeated measures ANOVA. Cows in the RP-BCAA and RP-BCAAPG groups had lower liver TG and lower activities of aspartate aminotransferase and glutamate dehydrogenase during the first 21 DIM, compared with control. All cows, regardless of treatment, showed an upregulation of p-BCKDH-E1α at d 5 postpartum, compared with levels at 21 d postpartum. Insulin, Met, and Glu blood concentration were greater in RP-BCAA and RP-BCAAPG compared with control during the first 35 DIM. Therefore, the use of RP-BCAA in combination with PG might be a feasible option to reduce hepatic lipidosis in dairy cows during early lactation.

Are Supplemental Branched-Chain Amino Acids Beneficial During the Oncological Peri-Operative Period: A Systematic Review and Meta-Analysis

BACKGROUND

Branched-chain amino acids (BCAAs; leucine, isoleucine, and valine) are essential amino acids involved in immune responses, and may have roles in protein malnutrition and sarcopenia. Furthermore, certain liver diseases have been associated with a decreased Fischer's ratio (BCAAs to aromatic amino acids; phenylalanine, tyrosine, and tryptophan). We aimed to evaluate the safety and efficacy of BCAAs use in patients with cancer undergoing surgery.

METHODS

MEDLINE, Embase, and CENTRAL were searched (inception to July 24, 2020) for randomized controlled trials (RCTs) and comparative observational studies in English evaluating BCAAs (alone or in combinations) during the oncological peri-operative period. Study selection, data extraction, and quality appraisal were done in duplicate. RCT risk-of-bias was appraised using Cochrane Risk-of-Bias tool, and observational studies' quality assessment was conducted with Newcastle-Ottawa Scale. Meta-analyses were conducted when appropriate.

RESULTS

20 articles were included comprising 13 RCTs and 6 observational cohort studies in 7 reports and 2019 total participants overall. Among 13 RCTs, 77% involved liver cancer. Methodological study quality scored substantial risk-of-bias across most RCTs. Meta-analysis of RCTs found a 38% decreased risk of post-operative infections in BCAAs group compared to controls (RR = 0.62; 95% CI = 0.44 to 0.87; P = .006; number of RCTs, k = 6; total sample size, N = 389; I² = 0%). BCAAs were also found to be beneficial for ascites (RR = 0.55; 95% CI = 0.35 to 0.86; P = .008; k = 4; N = 296; I² = 0%), body weight (MD = 3.24 kg; 95% CI = 0.44 to 6.04; P = .02; k = 3; N = 196; I² = 24%), and hospitalization length (MD = -2.07 days; 95% CI = -3.97 to -0.17; P = .03; k = 5; N = 362; I² = 59%). No differences were found between BCAAs and controls for mortality, recurrence, other post-operative complications (liver failure, edema, pleural effusion), blood loss, quality of life, ammonia level, and prothrombin time. No serious adverse events were related to BCAAs; however, serious adverse events were reported due to intravenous catheters. No safety concerns from observational studies were identified.

CONCLUSIONS

Branched-chain amino acids during the oncological surgical period demonstrated promise in reducing important post-operative morbidity from infections and ascites compared to controls. Blinded, placebo-controlled confirmatory trials of higher methodological quality are warranted, especially using oral, short-term BCAAs-enriched supplements within the context of recent ERAS programs.

PROSPERO REGISTRATION

CRD42018086168.

A Comprehensive Review Evaluating the Impact of Protein Source (Vegetarian vs. Meat Based) in Hepatic Encephalopathy

Hepatic encephalopathy (HE) is a common neurological consequence in patients with cirrhosis and has a healthcare burden of USD 5370 to 50,120 per patient annually. HE significantly hampers the quality of life and is a major cause of morbidity and mortality. Patients with cirrhosis are at a high risk for protein-calorie malnutrition due to altered metabolism. Current evidence has changed the old belief of protein restriction in patients with cirrhosis and now 1.2 to 1.5 g/kg/day protein intake is recommended. Case series and studies with small numbers of participants showed that a vegetarian protein diet decreases the symptoms of HE when compared to a meat-based diet, but the evidence is limited and requires further larger randomized controlled trials. However, vegetable or milk-based protein diets are good substitutes for patients averse to meat intake. Branch chain amino acids (BCAA) (leucine, isoleucine and valine) have also been shown to be effective in alleviating symptoms of HE and are recommended as an alternative therapy in patients with cirrhosis for the treatment of HE. In this review, we provide an overview of current literature evaluating the role of protein intake in the management of HE in cirrhosis.

Nutrition in Chronic Liver Disease: A Point-of-Care Review

Patients with chronic liver disease have a very high lifetime risk of malnourishment. It has been increasingly identified in literature that the severity of liver disease affects severity of malnutrition and vice versa. The objective of this review article is to recognize the severity of complications associated with malnutrition in patients with cirrhosis and ways to overcome these obstacles.

Loss of BCAA Catabolism during Carcinogenesis Enhances mTORC1 Activity and Promotes Tumor Development and Progression

Tumors display profound changes in cellular metabolism, yet how these changes aid the development and growth of tumors is not fully understood. Here we use a multi-omic approach to examine liver carcinogenesis and regeneration, and find that progressive loss of branched-chain amino acid (BCAA) catabolism promotes tumor development and growth. In human hepatocellular carcinomas and animal models of liver cancer, suppression of BCAA catabolic enzyme expression led to BCAA accumulation in tumors, though this was not observed in regenerating liver tissues. The degree of enzyme suppression strongly correlated with tumor aggressiveness, and was an independent predictor of clinical outcome. Moreover, modulating BCAA accumulation regulated cancer cell proliferation in vitro, and tumor burden and overall survival in vivo. Dietary BCAA intake in humans also correlated with cancer mortality risk. In summary, loss of BCAA catabolism in tumors confers functional advantages, which could be exploited by therapeutic interventions in certain cancers.

Management of portal hypertension

Primary prophylaxis is advisable for all patients with moderate-sized or large esophageal varices. After the first episode of bleeding, secondary prophylaxis should be initiated to prevent rebleeding. Multiple treatment modalities are available for each circumstance. Optimal regimens have not yet been established but are under investigation. At present, nonselective beta-blockers are the drugs of choice for primary prophylaxis. In patients with actively bleeding varices, octreotide or, in rare cases, a combination of vasopressin and nitroglycerin is used in conjunction with endoscopic band ligation of the varices. Either a beta-blocker, band ligation, or a combination of the two is appropriate for secondary prophylaxis. The combination is often the better choice for patients for whom primary prophylaxis with beta-blockers has failed. As in any treatment situation, the specific approach must be tailored to clinical circumstances. The patient's preferences and willingness or ability to comply with the therapy must be taken into account as well as the physician's expertise. Interventions for hepatic encephalopathy predominantly focus on reducing the amount of ammonia absorbed or endogenously generated in the body. They include correction of precipitating factors, bowel cleansing, and lactulose therapy. In difficult cases, a combination of lactulose and neomycin, metronidazole, or rifaximin is recommended. Because the prognosis for patients with hepatic encephalopathy is generally poor, orthotopic liver transplantation should be considered.

An amino acid-electrolyte beverage may increase cellular rehydration relative to carbohydrate-electrolyte and flavored water beverages

BACKGROUND

In cases of dehydration exceeding a 2% loss of body weight, athletic performance can be significantly compromised. Carbohydrate and/or electrolyte containing beverages have been effective for rehydration and recovery of performance, yet amino acid containing beverages remain unexamined. Therefore, the purpose of this study is to compare the rehydration capabilities of an electrolyte-carbohydrate (EC), electrolyte-branched chain amino acid (EA), and flavored water (FW) beverages.

METHODS

Twenty men (n = 10; 26.7 ± 4.8 years; 174.3 ± 6.4 cm; 74.2 ± 10.9 kg) and women (n = 10; 27.1 ± 4.7 years; 175.3 ± 7.9 cm; 71.0 ± 6.5 kg) participated in this crossover study. For each trial, subjects were dehydrated, provided one of three random beverages, and monitored for the following three hours. Measurements were collected prior to and immediately after dehydration and 4 hours after dehydration (3 hours after rehydration) (AE = -2.5 ± 0.55%; CE = -2.2 ± 0.43%; FW = -2.5 ± 0.62%). Measurements collected at each time point were urine volume, urine specific gravity, drink volume, and fluid retention.

RESULTS

No significant differences (p > 0.05) existed between beverages for urine volume, drink volume, or fluid retention for any time-point. Treatment x time interactions existed for urine specific gravity (USG) (p < 0.05). Post hoc analysis revealed differences occurred between the FW and EA beverages (p = 0.003) and between the EC and EA beverages (p = 0.007) at 4 hours after rehydration. Wherein, EA USG returned to baseline at 4 hours post-dehydration (mean difference from pre to 4 hours post-dehydration = -0.0002; p > 0.05) while both EC (-0.0067) and FW (-0.0051) continued to produce dilute urine and failed to return to baseline at the same time-point (p < 0.05).

CONCLUSION

Because no differences existed for fluid retention, urine or drink volume at any time point, yet USG returned to baseline during the EA trial, an EA supplement may enhance cellular rehydration rate compared to an EC or FW beverage in healthy men and women after acute dehydration of around 2% body mass loss.

Nutrition therapy using a multidisciplinary team improves survival rates in patients with liver cirrhosis

OBJECTIVES

Very few reports thus far have clinically elucidated the advantages of a nutrition support team (NST) in the field of liver diseases. The present study retrospectively analyzed whether nutrition therapy for liver cirrhosis (LC), performed by a multidisciplinary team that includes registered dieticians, improves survival rates.

METHODS

In study 1, we compared survival rates between two groups of patients with LC to elucidate the effects of nutrition management by registered dieticians. The first group was comprised of 101 patients that received no dietary counseling from a dietician, and the second group was comprised of 133 patients that received nutritional counseling following nutrition assessment. In study 2, we split the patients who received nutritional counseling in study 1 into two groups and compared their survival rates with the objective of investigating the effects of a multidisciplinary team approach on survival rate. The first group was comprised of 51 patients that, in addition to regular nutritional counseling given by a dietician, regularly attended courses on liver disease given every 3 to 6 mo. The second group was comprised of 82 patients that did not attend the liver-disease courses.

RESULTS

During study 1, 34 patients in the first group and 20 patients in the second group died, representing a significant difference (P < 0.05). This difference was even more pronounced in the subset of patients classified as Child-Pugh class A (P < 0.01), but no differences were seen among patients in classes B and C (P = 0.378). During study 2, four patients in the first group and 15 patients in the second group died, representing a significant difference (P < 0.05).

CONCLUSIONS

This study showed that nutritional intervention using a multidisciplinary team during the treatment of LC improves survival rates and quality of life of the patients.

Branched-chain amino acids enhance premature senescence through mammalian target of rapamycin complex I-mediated upregulation of p21 protein

Branched-chain amino acids (BCAAs) have been applied as an oral supplementation to patients with liver cirrhosis. BCAAs not only improve nutritional status of patients but also decrease the incidence of liver cancer. Mammalian target of rapamycin (mTOR) links cellular metabolism with growth and proliferation in response to nutrients, energy, and growth factors. BCAAs, especially leucine, have been shown to regulate protein synthesis through mTOR activities. On the other hand, cellular senescence is suggested to function as tumor suppressor mechanisms, and induced by a variety of stimuli including DNA damage-inducing drugs. However, it is not clear how BCAA supplementation prevents the incidence of liver cancer in patients with cirrhosis. Here we showed that human cancer cells, HepG2 and U2OS, cultured in medium containing BCAAs with Fischer's ratio about 3, which was shown to have highest activities to synthesize and secrete of albumin, had higher activities to induce premature senescence and elevate mTORC1 activities. Furthermore, BCAAs themselves enhanced the execution of premature senescence induced by DNA damage-inducing drugs, which was effectively prevented by rapamycin. These results strongly suggested the contribution of the mTORC1 pathway to the regulation of premature senescence. Interestingly, the protein levels of p21, a p53 target and well-known gene essential for the execution of cellular senescence, were upregulated in the presence of BCAAs. These results suggested that BCAAs possibly contribute to tumor suppression by enhancing cellular senescence mediated through the mTOR signalling pathway.

Effect of a carbohydrate-containing late-evening snack on energy metabolism and fasting substrate utilization in adults with acute-on-chronic liver failure due to Hepatitis B

BACKGROUND/OBJECTIVES

This study investigates the effects of a carbohydrate (CHO; lotus-root starch) predominant, late-evening snack (LES), containing 200 kcal (50 g CHO) on fasting resting energy expenditure (REE) and nutrient oxidation in hospitalized adults with acute-on-chronic liver failure (ACLF).

SUBJECTS/METHODS

Adults with ACLF were randomized to receive daily LES (treatment; n=35) or standard care (n=35; non-supplemented control) for 14 days. REE and respiratory quotient (RQ) were measured by indirect calorimetry, nutrient oxidation (CHO, protein and fat), intake and biochemical parameters were measured in both groups at baseline and after 14 days using validated techniques. Disease severity was measured using the model for end-stage liver disease (MELD).

RESULTS

No significant differences in macronutrient intake, anthropometric, demographic characteristics or MELD scores were observed between groups at baseline (P>0.05). Fasting RQ was significantly higher in the LES supplemented verses the control group after 2 weeks (P=0.02). CHO oxidation was significantly higher (P=0.001) and fat oxidation (P=0.02) was lower in the LES-supplemented group when compared with controls after 2 weeks. Fasting RQ and REE in the LES-supplemented group increased significantly (0.83 verses 0.88; P=0.007/1301±409 vs 1687±718 kcal/day; P=0.02) in patients with MELD scores 30 when compared with patients with MELD scores >30 (0.82 verses 0.84; P=0.27/ 1361±405 vs 1437±429 kcal/day; P=0.67) after supplementation.

CONCLUSIONS

A carbohydrate-predominant LES is associated with increases in fasting carbohydrate oxidation, REE and reductions in fat oxidation in adults with ACLF. Therapeutic strategies utilizing LES may promote improved nutritional status in adults with ACLF.

Branched-chain amino acid supplementation: impact on signaling and relevance to critical illness

The changes that occur in mammalian systems following trauma and sepsis, termed systemic inflammatory response syndrome, elicit major changes in carbohydrate, protein, and energy metabolism. When these events persist for too long they result in a severe depletion of lean body mass, multiple organ dysfunction, and eventually death. Nutritional supplementation has been investigated to offset the severe loss of protein, and recent evidence suggests that diets enriched in branched-chain amino acids (BCAAs) may be especially beneficial. BCAAs are metabolized in two major steps that are differentially expressed in muscle and liver. In muscle, BCAAs are reversibly transaminated to the corresponding α-keto acids. For the complete degradation of BCAAs, the α-keto acids must travel to the liver to undergo oxidation. The liver, in contrast to muscle, does not significantly express the branched-chain aminotransferase. Thus, BCAA degradation is under the joint control of both liver and muscle. Recent evidence suggests that in liver, BCAAs may perform signaling functions, more specifically via activation of mTOR (mammalian target of rapamycin) signaling pathway, influencing a wide variety of metabolic and synthetic functions, including protein translation, insulin signaling, and oxidative stress following severe injury and infection. However, understanding of the system-wide effects of BCAAs that integrate both metabolic and signaling aspects is currently lacking. Further investigation in this respect will help rationalize the design and optimization of nutritional supplements containing BCAAs for critically ill patients.

Consilience in sarcopenia of cirrhosis

Cirrhosis is the consequence of progression of many forms of necro-inflammatory disorders of the liver with hepatic fibrosis, hepatocellular dysfunction, and vascular remodeling. Reversing the primary hepatic disorder, liver transplantation, and controlling the complications are the major management goals. Since the former options are not available to the majority of cirrhotics, treating complications remains the mainstay of therapy. Sarcopenia and/or cachexia is the most common complication and adversely affects survival, quality of life, development of other complications of cirrhosis, and outcome after liver transplantation. With the increase in number of cirrhotic patients with hepatitis C and nonalcoholic fatty liver disease, the number of patients waiting for a liver transplantation is likely to continue to increase above the currently estimated 72.3/100,000 population. One of the critical clinical questions is to determine if we can treat sarcopenia of cirrhosis without transplantation. No effective therapies exist to treat sarcopenia because the mechanism(s) of sarcopenia in cirrhosis is as yet unknown. The reasons for this include the predominantly descriptive studies to date and the advances in our understanding of skeletal muscle biology and molecular regulation of atrophy and hypertrophy not being translated into the clinical practice of hepatology. Satellite cell biology, muscle autophagy and apoptosis, and molecular signaling abnormalities in the skeletal muscle of cirrhotics are also not known. Aging of the cirrhotic and transplanted population, use of mTOR inhibitors, and the lack of definitive outcome measures to define sarcopenia and cachexia in this population add to the difficulty in increasing our understanding of hepatic sarcopenia/cachexia and developing treatment options. Recent data on the role of myostatin, AMP kinase, impaired mTOR signaling resulting in anabolic resistance in animal models, and the rapidly developing field of nutriceuticals as signaling molecules need to be evaluated in human cirrhotics. Finally, the benefits of exercise reported in other disease states with sarcopenia may not be safe in cirrhotics due to the risk of gastrointestinal variceal bleeding due to an increase in portal pressure. This article focuses on the problems facing both muscle biologists and hepatologists in developing a comprehensive approach to sarcopenia in cirrhosis.

Protective effect of Phellinus linteus polysaccharide extracts against thioacetamide-induced liver fibrosis in rats: a proteomics analysis

Background

The hepatoprotective potential of Phellinus linteus polysaccharide (PLP) extracts has been described. However, the molecular mechanism of PLP for the inhibition of liver fibrosis is unclear. This study aims to investigate the molecular protein signatures involved in the hepatoprotective mechanisms of PLP via a proteomics approach using a thioacetamide (TAA)-induced liver fibrosis rat model.

Methods

Male Sprague–Dawley rats were divided into three groups of six as follows: Normal group; TAA group, in which rats received TAA only; and PLP group, in which rats received PLP and TAA. Liver fibrosis was induced in the rats by repeated intraperitoneal injections of TAA at a dose of 200 mg/kg body weight twice a week for 4 weeks. PLP was given orally at a dose of 50 mg/kg body weight twice a day from the beginning of the TAA treatment until the end of the experiment. The development of liver cirrhosis was verified by histological examination. Liver proteomes were established by two-dimensional gel electrophoresis. Proteins with significantly altered expression levels were identified by matrix-assisted laser desorption/ionization-time of flight/time of flight mass spectrometry and the differentially expressed proteins were validated by immunohistochemical staining and reverse transcription polymerase chain reaction.

Results

Histological staining showed a remarkable reduction in liver fibrosis in the rats with PLP treatment. A total of 13 differentially expressed proteins including actin, tubulin alpha-1C chain, preprohaptoglobin, hemopexin, galectin-5, glutathione S-transferase alpha-4 (GSTA4), branched chain keto acid dehydrogenase hterotetrameric E1 subunit alpha (BCKDHA), glutathione S-transferase mu (GSTmu); glyceraldehyde-3-phosphate dehydrogenase (GAPDH); thiosulfate sulfurtransferase (TFT); betaine-homocysteine S-methyltransferase 1 (BHMT1); quinoid dihydropteridine reductase (QDPR); ribonuclease UK114 were observed between the TAA and PLP groups. These proteins are involved in oxidative stress, heme and iron metabolism, cysteine metabolism, and branched-chain amino acid catabolism.

Conclusion

The proteomics data indicate that P. linteus may be protective against TAA-induced liver fibrosis via regulation of oxidative stress pathways, heat shock pathways, and metabolic pathways for amino acids and nucleic acids.

Branched-chain amino acid-enriched nutrients stimulate antioxidant DNA repair in a rat model of liver injury induced by carbon tetrachloride

Oxidative stress (OS) plays an important role in the progression of chronic liver disease including organ injury and hypoalbuminemia. Long-term oral supplementation with branched-chain amino acids (BCAAs) can inhibit liver dysfunction but their role in the prevention of liver fibrosis and injury to the liver is unclear. The aim of this study was to assess how BCAAs preserve liver function from OS. To investigate how BCAAs specifically prevent OS, we evaluated the effect of oral supplementation with BCAAs on OS using a rat liver cirrhosis model. Liver cirrhosis was induced in ten male Sprague-Dawley rats by administering carbon tetrachloride for 12 weeks. Five of the ten carbon tetrachloride-treated rats were assigned to a control group and five to a BCAA group. BCAA-supplementation significantly preserved plasma albumin concentrations and significantly inhibited the occurrence of organ injury as determined by blood chemistry analysis. Hepatic expression of OGG1 mRNA was increased in the BCAA group compared to the control group. In the BCAA group, increased hepatic levels of OGG1 protein were found by western blot. On the other hand, the number of 8-OHdG-positive cells was significantly higher in liver sections taken 1 month after carbon tetrachloride treatment. Furthermore, OGG1-positive cells were significantly increased in the hepatocytes around the central vein. BCAA was found to reduce OS, which could possibly lead to a decrease in the occurrence of hypoalbuminemia and organ injury. Our results indicate that BCAA-enriched nutrients stimulate antioxidant DNA repair in a rat model of liver injury induced by carbon tetrachloride.

Branched-chain amino acids prevent insulin-induced hepatic tumor cell proliferation by inducing apoptosis through mTORC1 and mTORC2-dependent mechanisms

Branched-chain amino acids (BCAA) supplementation has been reported to suppress the incidence of liver cancer in obese patients with liver cirrhosis or in obese and diabetic model animals of carcinogenesis. Whether BCAA directly suppresses cell proliferation of hepatic tumor cells under hyperinsulinemic condition remain to be defined. The aim of this study was to investigate the effects of BCAA on insulin-induced proliferation of hepatic tumor cells and determine the underlying mechanisms. BCAA suppressed insulin-induced cell proliferation of H4IIE, HepG2 cells. In H4IIE cells, BCAA did not affect cell cycle progression but increased apoptosis by suppressing expressions of anti-apoptotic genes and inducing pro-apoptotic gene via inactivation of PI3K/Akt and NF-κB signaling pathways. Further studies demonstrated that BCAA inhibited PI3K/Akt pathway not only by promoting negative feedback loop from mammalian target of rapamycin complex 1 (mTORC1)/S6K1 to PI3K/Akt pathway, but also by suppressing mTORC2 kinase activity toward Akt. Our findings suggest that BCAA supplementation may be useful to suppress liver cancer progression by inhibiting insulin-induced PI3K/Akt and subsequent anti-apoptotic pathway, indicating the importance of BCAA supplementation to the obese patients with advanced liver disease.

Changes in body composition after transjugular intrahepatic portosystemic stent in cirrhosis: a critical review of literature

Change in body composition with reduced muscle mass with or without loss of fat mass occurs in 60-90% of patients with cirrhosis. This has an adverse impact on the outcome of these patients and is an understudied area. Transjugular intrahepatic portosystemic stent (TIPS) is now a standard therapy for portal hypertension but its beneficial impact on nutritional indices is not well recognized. We included all publications on TIPS that had any nutritional index as an outcome measure or end point. Given the heterogeneity of the patient population, differences in study design and outcome measures, a meta-analysis was not feasible. Data were summarized and interpreted. A total of eight studies have been published on the changes in body composition after TIPS in cirrhosis in a total of 152 patients followed for 3-12 months. Improvement in fat-free mass and fluid-free or ascites-free body weight was reported in all studies. Plasma leptin, IGF1, insulin sensitivity, rate of glucose disposal and growth hormone did not change after TIPS. One study measured muscle strength that improved. Direct measurement of skeletal muscle mass was not performed in any study. TIPS resulted in an improvement in body composition. Given the clinical significance of skeletal muscle and fat mass in cirrhosis, nutritional indices should be considered to be an important outcome measure in patients with TIPS. The mechanism of these is unclear, but its clinical implication is that this may contribute to the improved survival after TIPS.

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.

Low-protein diets for hepatic encephalopathy debunked: let them eat steak

Hepatic encephalopathy (HE) is an incompletely understood phenomenon and serves as a poor prognosis in patients with cirrhosis. Confusion from HE can affect the ability to eat adequately. Despite the prevalence of malnutrition in cirrhotic patients in the 1950s, it was reported that bouts of overt HE were controlled with low protein intake. This largely uncontrolled observation led to restriction of protein intake in cirrhotic patients with or without HE and was an accepted standard of care for many decades to follow. Published in 2004, the pivotal article "Normal Protein Diet for Episodic Hepatic Encephalopathy: Results of a Randomized Study" by Cordoba and colleagues was the first controlled study randomizing cirrhotic patients with HE to receive different amounts of dietary protein. At the completion of the study, the authors concluded that a normal-protein diet was safe and did not exacerbate HE. The Cordoba study suggests that low-protein diets should be abandoned. In light of this evidence, nutrition guidelines have proposed that protein restriction should be avoided in patients with HE as protein requirements are increased in cirrhosis. Despite the advice of experts in the field, it has been shown in recent years that some physicians still believe that protein restriction is needed in patients with HE. This belief has not been substantiated in controlled studies, and societal recommendations have changed. There is no real evidence documenting the advantages of protein restriction in HE. On the contrary, Cordoba and colleagues' article has shown that there are disadvantages to restricting protein in HE.

Portale Hypertension

Während die Pathologie, die zur portalen Hypertension führt, im prähepatischen, hepatischen und posthepatischen venösen Gefäßbett liegen kann, machen die intrahepatischen Erkrankungen mit Abstand den Großteil aus. In unseren Breitengraden ist es die durch Alkoholabusus bedingte ethyltoxische Leberzirrhose, weltweit die durch Infektionen (HCV, HBV) bedingten Zirrhosen. Die chronische Hepatitis C mit ihren Komplikationen (Leberzellversagen, portale Hypertension und hepatozelluläres Karzinom) wird in den kommenden Jahren trotz moderner Therapieverfahren noch an Bedeutung gewinnen.

Nutrition in hepatic encephalopathy

Protein calorie malnutrition (PCM) is a well-known complication of chronic liver disease (CLD). A major contribution to PCM in CLD is restriction of dietary protein intake. After many decades of injudicious reduction in dietary protein, cirrhotic patients are now prescribed appropriate amounts of protein. PCM in CLD is known to be associated with life-threatening complications. In the general approach to these patients, the initial and most important step for the clinician is to recognize the extent of malnutrition. Most patients tolerate a normal amount of dietary protein without developing hepatic encephalopathy (HE). Oral branched-chain amino acids (BCAAs) have a limited role in HE. Patients who exhibit dietary protein intolerance originally were thought to be best treated with BCAA formulations. Mixed evidence has been reported in multiple studies. In keeping with other reports, this article shows that in animal protein-intolerant patients, even those with advanced cirrhosis, vegetable protein-based diets are well tolerated. Another approach to management of apparent dietary intolerance is to optimize HE treatment with available medications. This article reviews the causes of HE, minimal HE, and PCM; examines nutrition requirements and assessment; and discusses treatment options for malnutrition in HE.

Oral supplementation with carbohydrate- and branched-chain amino acid-enriched nutrients improves postoperative quality of life in patients undergoing hepatic resection

The long-term outcomes of branched-chain amino acid (BCAA) administration in patients undergoing hepatic resection remain unclear. The aim of this study is to assess the impact of oral supplementation with BCAA-enriched nutrients on postoperative quality of life (QOL) in patients undergoing liver resection. A prospective randomized clinical trial was conducted in 96 patients undergoing hepatic resection. Patients were randomly assigned to receive BCAA supplementation (AEN group, n = 48) or a conventional diet (control group, n = 48). Postoperative QOL and short-term outcomes were regularly and continuously evaluated in all patients using a short-form 36 (SF-36) health questionnaire and by measuring various clinical parameters. This study demonstrated a significant improvement in QOL after hepatectomy for liver neoplasm in the AEN group based on the same patients' preoperative SF-36 scores (P < 0.05). Perioperative BCAA supplementation preserved liver function and general patient health in the short term for AEN group patients compared to those not receiving the nutritional supplement. BCAA supplementation improved postoperative QOL after hepatic resection over the long term by restoring and maintaining nutritional status and whole-body kinetics. This study was registered at http://www.clinicaltrials.gov (registration number: NCT00945568).

The impact of nutrition on cirrhotic patients awaiting liver transplantation

PURPOSE OF REVIEW

To review the most recent aspects of nutrition therapy of cirrhotic patients on the waiting list for liver transplantation.

RECENT FINDINGS

Undernutrition has been widely reported among these patients, despite the lack of consensus on the best nutritional assessment tools in this population. Nutrition therapy has been marked by controversy. Nonetheless, recent findings have pointed out to the important role of the nutrition status and of some specific nutrients on the outcome of these patients.

SUMMARY

We report the latest findings on nutrition care of patients with end-stage liver disease on the waiting list for liver transplantation such as the impact of the nutritional status on outcome, probiotic and branched-chain amino acid supplementation, as well as the use of immunomodulating formula. Another important strategy that has been shown to improve these patients' nutritional care is the offering of nocturnal meals and micronutrient supplementation.

Three targets of branched-chain amino acid supplementation in the treatment of liver disease

The article explains the pathogenesis of disturbances in branched-chain amino acid (BCAA; valine, leucine, and isoleucine) and protein metabolism in various forms of hepatic injury and it is suggested that the main cause of decrease in plasma BCAA concentration in liver cirrhosis is hyperammonemia. Three possible targets of BCAA supplementation in hepatic disease are suggested: (1) hepatic encephalopathy, (2) liver regeneration, and (3) hepatic cachexia. The BCAA may ameliorate hepatic encephalopathy by promoting ammonia detoxification, correction of the plasma amino acid imbalance, and by reduced brain influx of aromatic amino acids. The influence of BCAA supplementation on hepatic encephalopathy could be more effective in chronic hepatic injury with hyperammonemia and low concentrations of BCAA in blood than in acute hepatic illness, where hyperaminoacidemia frequently develops. The favorable effect of BCAA on liver regeneration and nutritional state of the body is related to their stimulatory effect on protein synthesis, secretion of hepatocyte growth factor, glutamine production and inhibitory effect on proteolysis. Presumably the beneficial effect of BCAA on hepatic cachexia is significant in compensated liver disease with decreased plasma BCAA concentrations, whereas it is less pronounced in hepatic diseases with inflammatory complications and enhanced protein turnover. It is concluded that specific benefits associated with BCAA supplementation depend significantly on the type of liver disease and on the presence of inflammatory reaction. An important task for clinical research is to identify groups of patients for whom BCAA treatment can significantly improve the health-related quality of life and the prognosis of hepatic disease.

Role of branched-chain amino acids in management of cirrhosis and hepatocellular carcinoma

Altered protein and energy metabolism is a hallmark of chronic liver disease, characterized by decreased plasma branched-chain amino acids (BCAA) and increased plasma aromatic amino acids (AAA). Overwhelming evidence has indicated that the incidence of complications of chronic liver disease increases with malnutrition. Hence nutritional management in patients with chronic liver disease must receive high priority. The use of BCAA supplementation has been a controversial subject. This review summarizes published results of BCAA supplementation as a nutritional therapy for patients with cirrhosis and hepatocellular carcinoma (HCC). On balance, it would be appropriate to conclude that BCAA are associated with decreased frequency of complications of cirrhosis and improved nutritional status when prescribed as a maintenance therapy for patients with cirrhosis. More studies are, however, required to identify those who might benefit most from BCAA supplementation.

Randomized, Controlled Study of Branched Chain Amino Acid-Enriched Total Parenteral Nutrition in Malnourished Patients with Gastrointestinal Cancer Undergoing Surgery

The objective of this study was to investigate the potential benefit of branched chain amino acid (BCAA)-enriched total parenteral nutrition (TPN) for malnourished surgical patients with gastrointestinal cancer. Sixty-four malnourished patients with gastrointestinal cancer with elective surgical intervention were equally allocated into two groups to receive isonitrogenous and iso-caloric TPN. All of them must have received TPN soon after surgery and were subsequently randomized and divided into either BCAA-enriched TPN (30% BCAA; intervention group) or standard TPN (24% BCAA; control group). Patient biochemical data, nutritional parameters, and clinical outcome were collected to analyze the significance of BCAA-enriched TPN. After a period of TPN, laboratory data, including white blood cell (WBC), C-reactive protein (CRP), alkaline phosphatase (ALK-P), and gamma-glutamyltransferase (γ-GT) levels, were significantly different between these two groups (all P < 0.05). Decreasing white blood cell and C-reactive protein levels were observed in the intervention group that might partially explain the reduced numbers of infectious complications. Furthermore, elevating alkaline phosphatase and gamma-glutamyltransferase levels being also less prominent might indicate a lesser hepatic burden by using BCAA-enriched TPN. The BCAA-enriched TPN can maintain a patient's serum visceral protein (albumin and prealbumin) and positive nitrogen balance better than standard TPN (all P < 0.05). Furthermore, a prominently decreased frequency of postoperative morbidity was also found in the BCAA-enriched TPN group (P = 0.021) despite no difference regarding surgical mortality. Our observations show that BCAA-enriched TPN may be beneficial in improving the nutritional status and reducing postoperative complications for malnourished patients with gastrointestinal cancer undergoing major surgery.

Branched-chain amino acids improve insulin resistance in patients with hepatitis C virus-related liver disease: report of two cases

Hepatitis C virus (HCV) infection causes insulin resistance. Because increased insulin resistance is a risk factor for development of hepatocellular carcinoma and reduced long-term survival, insulin resistance is a therapeutic target in patients with HCV infection. Branched-chain amino acids (BCAAs) are not only structural constituents of proteins but they are also considered as regulators of insulin signalling. We first describe two cases suggesting that administration of BCAAs improves insulin resistance associated with HCV-related liver disease. Although there were no changes in body weight, plasma glucose concentration and haemoglobin A1c (HbA1c) value were decreased. Moreover, BCAAs caused a decrease in both fasting insulin concentration and the value of homeostasis model assessment for insulin resistance. Thus, BCAAs are a potential therapeutic agent for improving insulin resistance in patients with HCV-related liver disease.

Mechanisms and outcomes of drug- and toxicant-induced liver toxicity in diabetes

Increase dincidences of hepatotoxicity have been observed in diabetic patients receiving drug therapies. Neither the mechanisms nor the predisposing factors underlying hepatotoxicity in diabetics are clearly understood. Animal studies designed to examine the mechanisms of diabetes-modulated hepatotoxicity have traditionally focused only on bioactivation/detoxification of drugs and toxicants. It is becoming clear that once injury is initiated, additional events determine the final outcome of liver injury. Foremost among them are two leading mechanisms: first, biochemical mechanisms that lead to progression or regression of injury; and second, whether or not timely and adequate liver tissue repair occurs to mitigate injury and restore liver function. The liver has a remarkable ability to repair and restore its structure and function after physical or chemical-induced damage. The dynamic interaction between biotransformation-based liver injury and compensatory tissue repair plays a pivotal role in determining the ultimate outcome of hepatotoxicity initiated by drugs or toxicants. In this review, mechanisms underlying altered hepatotoxicity in diabetes with emphasis on both altered bioactivation and liver tissue repair are discussed. Animal models of both marked sensitivity (diabetic rats) and equally marked protection (diabetic mice) from drug-induced hepatotoxicity are described. These examples represent a remarkable species difference. Availability of the rodent diabetic models offers a unique opportunity to uncover mechanisms of clinical interest in averting human diabetic sensitivity to drug-induced hepatotoxicities. While the rat diabetic models appear to be suitable, the diabetic mouse models might not be suitable in preclinical testing for potential hepatotoxic effects of drugs or toxicants, because regardless of type 1 or type2 diabetes, mice are resistant to acute drug-or toxicant-induced toxicities.

Lowered concentrations of branched-chain amino acids result in impaired growth and neurological problems: insights from a branched-chain alpha-keto acid dehydrogenase complex kinase-deficient mouse model

Excess circulating levels of branched-chain amino acids (BCAA), as seen in maple syrup urine disease, result in severe neuropathology. A new mouse model, deficient in the kinase that controls BCAA catabolism, shows that very low circulating levels of BCAA are also associated with neuropathology, including the development of epileptic seizures. These mice clearly demonstrate the need to control essential amino acid levels within both upper and lower limits.

Role of branched-chain amino acids in liver disease: the evidence for and against

PURPOSE OF REVIEW

There is ample evidence that patients with liver disease have an ongoing energy and protein catabolism. Nutritional management in these patients must receive high priority. The administration of branched-chain amino acids to patients with liver disease has been a controversial subject. This review is an update on the data available from various studies involving branched-chain amino acids supplementation in patients with chronic liver disease and associated complications.

RECENT FINDINGS

This review summarizes the results of nutritional interventions involving branched-chain amino acids supplementation carried out in different centres around the world. It is interesting to note that no toxic effects of branched-chain amino acids supplementation have been reported in any of these trials.

SUMMARY

Administration of branched-chain amino acids stimulates hepatic protein synthesis in patients with chronic liver disease and this could contribute significantly to improving their nutritional status, and result in a better quality of life. The beneficial role of branched-chain amino acids supplementation in patients with chronic hepatic encephalopathy has been clearly documented in some studies but the exact mechanism of action is still not clear.

Supplementation of soy protein with branched-chain amino acids alters protein metabolism in healthy elderly and even more in patients with chronic obstructive pulmonary disease

BACKGROUND

It is often suggested that chronic wasting diseases [eg, chronic obstructive pulmonary disease (COPD)] may benefit from branched-chain amino acid (BCAA) administration via improved protein metabolism.

OBJECTIVE

The aim was to examine whether adding BCAAs to a soy protein meal would enhance protein anabolism in COPD patients and in healthy elderly persons.

DESIGN

Eight normal-weight COPD patients and 8 healthy control subjects were examined on 2 test days. Simultaneous continuous intravenous infusion of l-[ring-(2)H(5)]phenylalanine (Phe) and l-[ring-(2)H(2)]tyrosine tracers was done postabsorptively and at 2 h of ingestion of a maltodextrin soy or maltodextrin soy + BCAA protein meal (rate of ingestion: 0.02 g protein.kg body weight(-1).20 min(-1)) in a crossover design. Together with the meal, oral ingestion of 1-[(13)C]Phe was performed to measure first-pass Phe splanchnic extraction (SPE(Phe)). The endogenous rate of Phe appearance [reflecting whole-body protein breakdown (WbPB)], whole-body protein synthesis (WbPS), and net WbPS (WbPS - WbPB) were calculated. Arterialized venous blood was sampled for amino acid enrichment and concentration analyses.

RESULTS

Soy feeding induced a reduction in WbPB and an increase in WbPS. BCAA supplementation of soy protein resulted in a significantly higher (P < 0.05) increase in WbPS than did soy protein alone in COPD patients but not in the healthy elderly. BCAA supplementation did not significantly alter the change in WbPB or net WbPS. Furthermore, BCAA supplementation decreased (absolute) SPE(Phe) (P < 0.05) but did not change the percentage Phe hydroxylation in the splanchnic area, which indicates a BCAA-related reduction in splanchnic protein synthesis.

CONCLUSION

BCAA supplementation to soy protein enhances WbPS in patients with COPD and alters interorgan protein metabolism in favor of the peripheral (muscle) compartment in healthy elderly and even more in COPD patients.

Management of hepatic encephalopathy in patients with cirrhosis

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

Branched-chain amino acid needs in children with mild-to-moderate chronic cholestatic liver disease

Protein-energy malnutrition is prevalent in children with chronic cholestatic liver disease. Supplementation of branched-chain amino acids (BCAA) in infants and children with chronic liver disease has been associated with significant improvement in growth and nitrogen balance, suggesting that BCAA requirements are increased in chronic liver disease. The goal of the present study was to determine the total BCAA requirement in children with mild-to-moderate chronic cholestatic (MCC) liver disease using indicator amino acid oxidation (IAAO). Total BCAA requirements were determined in 6 children (6.3 +/- 3.7 y, mean +/- SD) with MCC liver disease. Children were randomly assigned to receive 7 graded intakes of total BCAA. Individual BCAA in the test diet were provided in the same proportions as those present in egg protein to minimize the potential interactive effects of individual BCAA on assessment of requirement. The total BCAA requirement was determined by measuring the oxidation of l-[1-13C] Phe to 13CO2 [F13CO2 in micromol/(kg x h)], after a primed, continuous oral administration of the tracer and using a 2-phase linear regression crossover regression analysis. The estimated mean requirement and the upper limit of the 95% CI for total BCAA establishing using the IAAO in children with MCC liver disease were 209 and 272 mg/(kg x d), respectively. Total BCAA estimated average requirements using the IAAO were significantly higher than mean requirements established previously for healthy children (P < 0.05).

Nitrogen isotopic composition in hair protein is different in liver cirrhotic patients

The stable-isotopic composition of nitrogen (delta15N) or carbon (delta13C) of body tissues depends on the isotopic composition of food sources and on shifts due to isotopic fractionation during metabolism. As little is known about the effects of pathophysiological conditions we measured delta15N and delta13C values in hair and hair amino acids of patients with cirrhosis (n = 21) and compared the results with those of healthy subjects (n = 100) randomly selected from the 1987-1988 VERA German nutrition survey population. Cirrhosis was reflected in lower hair 15N abundances (6.7 vs. 9.9 per thousand delta15N; P < 0.001) whereas hair 13C abundances did not differ from healthy subjects (-19.4 vs. -19.6 per thousand 13C). Distinct patterns of delta15N and delta13C values were measured in hair amino acids. The delta15N values of phenylalanine were significantly higher in cirrhotics (P < 0.001). With the exception of isoleucine, threonine, and proline all other measured amino acids showed lower delta15N values than healthy subjects (P < 0.001). Lower hair delta15N values were associated with cirrhotic liver disease which suggests that under this condition the altered liver amino acid metabolism affects the nitrogen isotopic composition of the amino acids used for hair protein synthesis. It remains to be determined in controlled studies whether the altered nitrogen isotopic composition directly reflects the pathophysiological condition or is related to differences in dietary protein intake from plant or animal food sources.

Role of enteral and parenteral nutrition in the patient with gastrointestinal and liver disease

This chapter discusses a number of key issues: the importance of nutritional support, both enteral (oral nutritional supplements, enteral tube feeding) and parenteral nutrition in the treatment of the nutritionally compromised patient with gastrointestinal and liver disease; prescribing and monitoring nutritional support; refeeding syndrome; practicalities, indications and contraindications and complications of using enteral and parenteral nutrition; choosing feeds with an optimal nutrient composition for nutritional support, including specific feeds for disease states; the evidence base for using nutritional support in the patient with gastrointestinal and liver disease.

Nutrition in end stage liver disease

This chapter will focus on studies within the last 5 years of nutrition in end stage liver disease, but earlier studies illustrating the present state of affairs will also be mentioned. The first part will focus on descriptive epidemiological studies that help to set the scene for the intervention studies, which will be described in the second part. Each part will discuss liver cirrhosis, acute liver failure and liver transplantation separately. The aim is to provide the reader with sufficient background for the decision in clinical practice about when to see nutrition support as an important part of treatment of the patient.