Effects of a late evening snack combined with alpha-glucosidase inhibitor on liver cirrhosis

Branched-Chain Amino Acids in Liver Diseases: Complexity and Controversy

Branched-chain amino acids (BCAAs), as essential amino acids, engage in various physiological processes, such as protein synthesis, energy supply, and cellular signaling. The liver is a crucial site for BCAA metabolism, linking the changes in BCAA homeostasis with the pathogenesis of a variety of liver diseases and their complications. Peripheral circulating BCAA levels show complex trends in different liver diseases. This review delineates the alterations of BCAAs in conditions including non-alcoholic fatty liver disease, hepatocellular carcinoma, cirrhosis, hepatic encephalopathy, hepatitis C virus infection, and acute liver failure, as well as the potential mechanisms underlying these changes. A significant amount of clinical research has utilized BCAA supplements in the treatment of patients with cirrhosis and liver cancer. However, the efficacy of BCAA supplementation in clinical practice remains uncertain and controversial due to the heterogeneity of studies. This review delves into the complicated relationship between BCAAs and liver diseases and tries to untangle what role BCAAs play in the occurrence, development, and outcomes of liver diseases.

Branched-chain Amino Acids: Catabolism in Skeletal Muscle and Implications for Muscle and Whole-body Metabolism

Branched-chain amino acids (BCAAs) are critical for skeletal muscle and whole-body anabolism and energy homeostasis. They also serve as signaling molecules, for example, being able to activate mammalian/mechanistic target of rapamycin complex 1 (mTORC1). This has implication for macronutrient metabolism. However, elevated circulating levels of BCAAs and of their ketoacids as well as impaired catabolism of these amino acids (AAs) are implicated in the development of insulin resistance and its sequelae, including type 2 diabetes, cardiovascular disease, and of some cancers, although other studies indicate supplements of these AAs may help in the management of some chronic diseases. Here, we first reviewed the catabolism of these AAs especially in skeletal muscle as this tissue contributes the most to whole body disposal of the BCAA. We then reviewed emerging mechanisms of control of enzymes involved in regulating BCAA catabolism. Such mechanisms include regulation of their abundance by microRNA and by post translational modifications such as phosphorylation, acetylation, and ubiquitination. We also reviewed implications of impaired metabolism of BCAA for muscle and whole-body metabolism. We comment on outstanding questions in the regulation of catabolism of these AAs, including regulation of the abundance and post-transcriptional/post-translational modification of enzymes that regulate BCAA catabolism, as well the impact of circadian rhythm, age and mTORC1 on these enzymes. Answers to such questions may facilitate emergence of treatment/management options that can help patients suffering from chronic diseases linked to impaired metabolism of the BCAAs.

The Effects of BCAAs on Insulin Resistance in Athletes

The toxic catabolic intermediates of branched chain amino acids can cause insulin resistance, and are involved in different mechanisms in different metabolic tissues. In skeletal muscle, 3-hydroxy-isobutyrate produced by valine promotes skeletal muscle fatty acid uptake, resulting in the accumulation of incompletely oxidized lipids in skeletal muscle, causing skeletal muscle insulin resistance. In the liver, branched-chain α-keto acids decompose in large amounts, promote hepatic gluconeogenesis, and lead to the accumulation of multiple acylcarnitines, which damages the mitochondrial tricarboxylic acid cycle, resulting in the accumulation of incomplete oxidation products, oxidative stress in mitochondria, and hepatic insulin resistance. In adipose tissue, the expression of branched-chain amino acid catabolic enzymes (branched-chain amino acid transaminase, branched-chain α-keto acid dehydrogenase) is reduced, resulting in an increased level of plasma branched-chain amino acids, thereby causing massive decomposition of branched-chain amino acids in tissues such as skeletal muscle and liver, and inducing insulin resistance. However, branched-chain amino acids, as a common nutritional supplement for athletes, do not induce insulin resistance. A possible explanation for this phenomenon is that exercise can enhance the mitochondrial oxidative potential of branched-chain amino acids, alleviate or even eliminate the accumulation of branched-chain amino acid catabolic intermediates, and promotes branched-chain amino acids catabolism into beta-aminoisobutyric acid, increasing plasma beta-aminoisobutyric acid concentration, improving insulin resistance. This article reveals the mechanism of BCAA-induced insulin resistance and the relationship between exercise and BCAAs metabolism, adds a guarantee for the use of BCAAs, and provides a new explanation for the occurrence of diabetes and how exercise improves diabetes.

Effects of Late Evening Snack on Cirrhotic Patients: A Systematic Review and Meta-Analysis

Background

Energetic effects of late evening snack (LES) on cirrhotic patients were reported recently, but there was no quantitative analysis. In this meta-analysis, we reviewed and quantified the effects of LES on energy metabolism and substrate oxidation in the patients with cirrhosis, which will be of benefit for liver cirrhosis nutritional therapy.

Methods

A systematic search was conducted in PubMed, Embase, Web of Science, Elsevier, China National Knowledge Infrastructure, and Wanfang Database for relevant trials published until July 2017. These studies statistically were combined and analyzed by RevMan 5.3.

Results

Fourteen trials comprising 478 cases were eligible for analysis. The results showed that the respiratory quotient value (MD = 11.09) and carbohydrate oxidation value (MD = 0.05) significantly elevated with one week or with up to three weeks of LES treatment in cirrhotic patients (P < 0.05). Meanwhile, the levels of serum albumin (MD = 2.98) and cholinesterase (SMD = 1.09) were increased with LES administration for three weeks or that lasting twelve weeks (P < 0.05). However, there was no significant improvement for the levels of alanine aminotransferase (ALT) (P = 0.53), aspartate aminotransferase (AST) (P = 0.96), and total bilirubin (TB) (P = 0.32).

Conclusions

LES could improve the energy malnutrition state of cirrhotic patients. However, it may have little effect on reducing liver parenchymal injury indexes such as serum aminotransferase.

Branched-chain amino acids in liver diseases

Branched chain amino acids (BCAAs) are involved in various bioprocess such as protein metabolism, gene expression, insulin resistance and proliferation of hepatocytes. BCAAs have also been reported to suppress the growth of hepatocellular carcinoma (HCC) cells in vitro and to be required for immune cells to perform the function. In advanced cirrhotic patients, it has been clarified that serum concentrations of BCAA are decreased, whereas those of aromatic amino acids (AAAs) are increased. These alterations are thought to be the causes of hepatic encephalopathy (HE), sarcopenia and hepatocarcinogenesis and may be associated with the poor prognosis of patients with these conditions. Administration of BCAA-rich medicines has shown positive results in patients with cirrhosis.

Effect of branched-chain amino acid supplementation on insulin resistance and quality of life in chronic hepatitis C patients

The incidence rate of insulin resistance (IR) in patients with chronic hepatitis C (CHC) is high. Recently, branched-chain amino acids (BCAA) have been shown to attenuate IR in CHC patients; however, their effect on patient quality of life remains unclear. Therefore, the aim of the current prospective study was to determine the effects of BCAA supplement on IR and health-related quality of life (HR-QoL) in patients with CHC. In the study, 20 non-diabetic patients with CHC, who were non-responders to peginterferon-α and ribavirin, were recruited. Patients took a BCAA supplement once a day (30 g, after a minimum 10-h overnight fast) for 3 months. Serum levels of glucose, insulin, albumin, triglycerides and cholesterol were measured at 0 and 3 months. Additionally, IR was measured using the Homeostasis Model Assessment-IR, HR-QoL was assessed using the 36-item Short Form Health Survey and viral load was measured by reverse transcription polymerase chain reaction using Taqman probes. The Wilcoxon signed-rank test was used to determine statistical significance. The results indicated that 70% of the subjects were positive for IR, which decreased to 50% by the end of the study; furthermore, 85% of the subjects demonstrated some level of improvement. Overall, the BCAA treatment significantly decreased IR (P=0.006) and augmented serum albumin concentration (P=0.008) compared with basal values. Additionally, by the end of the treatment, viral load and triglycerides levels had decreased, though these results were not significant (P=0.084 and P=0.080, respectively). BCAA treatment also improved HR-QoL regarding role limitations due to physical health problems (P=0.017), role limitations due to emotional problems (P=0.026) and social function (P=0.008). In conclusion, BCAA supplementation reduced IR and improved HR-QoL in patients with CHC. These findings support the application of IR therapy as a possible therapeutic strategy for hepatitis C infection.

Verification of glycemic profiles using continuous glucose monitoring: cases with steroid use, liver cirrhosis, enteral nutrition, or late dumping syndrome

Glycemic control is often difficult to achieve in patients with diabetes, especially in the presence of comorbid diseases or conditions such as steroid-use or liver cirrhosis, or in patients receiving enteral nutrition. Moreover, reactive hypoglycemia due to late dumping syndrome in people having undergone gastrectomy is also a matter of concern. Empirically and theoretically, the typical glycemic profiles associated with these conditions have been determined; however, what actually happens during a 24-h span is still somewhat obscure. In order to verify and provide information about the 24-h glycemic profiles associated with these conditions, 8 patients with the 4 above-mentioned conditions were monitored using a continuous glucose monitoring system (CGMS). For all 8 patients, CGMS provided detailed information regarding the 24-h glycemic profiles. The CGM results showed typical glycemic patterns for each condition, and we were moreover able to observe the effects of various practical treatments. Based on these cases, we conclude that the CGMS is highly useful for determining the glycemic patterns of patients with the aforementioned conditions in a practical setting; and this system may be used to monitor the treatment success of such cases.

Clinical usefulness of non-protein respiratory quotient measurement in non-alcoholic fatty liver disease

AIM

Little is known about the effects of non-alcoholic fatty liver disease (NAFLD) on energy metabolism, although this disease is associated with metabolic syndrome. We measured non-protein respiratory quotient (npRQ) using indirect calorimetry, which reflects glucose oxidation, and compared this value with histological disease severity in NAFLD patients.

METHODS

Subjects were 32 patients who were diagnosed with NAFLD histopathologically. Subjects underwent body composition analysis and indirect calorimetry, and npRQ was calculated. An oral glucose tolerance test was performed, and plasma glucose area under the curve (AUC glucose) was calculated.

RESULTS

There were no differences in body mass index, body fat percentage or visceral fat area among fibrosis stage groups. As fibrosis progressed, npRQ significantly decreased (stage 0, 0.895 ± 0.068; stage 1, 0.869 ± 0.067; stage 2, 0.808 ± 0.046; stage 3, 0.798 ± 0.026; P < 0.005). Glucose intolerance worsened and insulin resistance increased with fibrosis stage. npRQ was negatively correlated with AUC glucose (R = -0.6308, P < 0.001), Homeostasis Model of Assessment - Insulin Resistance (R = -0.5045, P < 0.005), fasting glucose (R = -0.4585, P < 0.01) and insulin levels (R = -0.4431, P < 0.05), suggesting that decreased npRQ may reflect impaired glucose tolerance due to insulin resistance, which was associated with fibrosis progression. Estimation of fibrosis stage using npRQ was as accurate as several previously established scoring systems using receiver-operator curve analysis.

CONCLUSION

npRQ was significantly decreased in patients with advanced NAFLD. Our data suggest that measurement of npRQ is useful for the estimation of disease severity in NAFLD patients.

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.

Effects of oral branched-chain amino acids on hepatic encephalopathy and outcome in patients with liver cirrhosis

Branched-chain amino acids (BCAAs) constituting of valine, leucine, and isoleucine act as both substrates of proteins and as key regulators for various nutrient metabolisms. Patients with liver cirrhosis frequently lack sufficient BCAAs and therefore suffer from various metabolic disorders. Hepatic encephalopathy (HE) is a severe metabolic disorder with neurologic manifestations such as flapping tremors and coma in patients with liver cirrhosis. In addition, a mild form of HE known as minimal HE (MHE) is an important social issue because it occurs in up to 80% of patients with chronic liver disease and affects prognosis and activities of daily living, possibly resulting in falls and motor vehicle accidents. Although HE/MHE can be caused by various pathological conditions, including in an accumulation of mercaptans, short-chain fatty acids, and alterations in the gut flora, hyperammonemia has also been implicated in an important pathogenesis of HE/MHE. Besides urea cycle of liver, ammonia can be detoxified in the skeletal muscles by the amidation process for glutamine synthesis using BCAAs. Thus, BCAA supplementation may enhance detoxification of ammonia in skeletal muscle and may be a possible therapeutic strategy for HE/MHE. In this review, we summarize the clinical impacts of BCAA supplementation on HE/MHE and discuss possible mechanisms for a BCAA-induced improvement of HE/MHE. Furthermore, we present some modifications of oral BCAA therapy for improvement of efficacy in HE treatment. We also briefly describe pleiotropic benefits of BCAAs on life-threatening events and overall prognosis in patients with liver cirrhosis.

Guidelines on nutritional management in Japanese patients with liver cirrhosis from the perspective of preventing hepatocellular carcinoma

AIM

  The Japanese Nutritional Study Group for Liver Cirrhosis (JNUS) was assembled in 2008 with the support of a Health Labor Sciences Research Grant from the Ministry of Health, Labor and Welfare of Japan. The goal of the study group was to propose new nutritional guidelines for Japanese patients with liver cirrhosis (LC), with the aim of preventing hepatocellular carcinoma.

METHODS

  Between 2008 and 2010, the member investigators of JNUS conducted various clinical and experimental studies on nutrition on LC. These included anthropometric studies, a questionnaire study on daily nutrient intake, clinical trials, experimental studies using animal models, re-evaluation of previous publications and patient education. Over this 3-year period, the group members regularly discussed the nutritional issues related to LC, and a proposal was finally produced.

RESULTS

  Based on the results of JNUS projects and discussions among the members, general recommendations were made on how Japanese patients with LC should be managed nutritionally. These recommendations were proposed with a specific regard to the prevention of hepatocarcinogenesis.

CONCLUSION

  The new JNUS guidelines on nutritional management for Japanese patients with LC will be useful for the actual nutritional management of patients with LC. The JNUS members hope that these guidelines will form the basis for future discussions and provide some direction in nutritional studies in the field of hepatology.

Branched-chain amino acids as pharmacological nutrients in chronic liver disease

Branched-chain amino acids (BCAAs) are a group of essential amino acids comprising valine, leucine, and isoleucine. A low ratio of plasma BCAAs to aromatic amino acids is a physiological hallmark of liver cirrhosis, and BCAA supplementation was originally devised with the intention of normalizing amino acid profiles and nutritional status. However, recent studies on BCAAs have revealed that, in addition to their role as protein constituents, they may have a role as pharmacological nutrients for patients with chronic liver disease. Large-scale, multicenter, randomized, double-blinded, controlled trials on BCAA supplementation have been performed in Italy and Japan, and results demonstrate that BCAA supplementation improves not only nutritional status, but also prognosis and quality of life in patients with liver cirrhosis. Moreover, accumulating experimental evidence suggests that the favorable effects of BCAA supplementation on prognosis may be supported by unforeseen pharmacological actions of BCAAs. This review summarizes the possible effects of BCAAs on albumin synthesis and insulin resistance from clinical and basic viewpoints. We also review the newly discovered clinical impact of BCAAs on hepatocellular carcinoma and the prognosis and quality of life of patients with liver cirrhosis.

Potential role of branched-chain amino acids in glucose metabolism through the accelerated induction of the glucose-sensing apparatus in the liver

Branched-chain amino acids (BCAAs) have a potential to improve glucose metabolism in cirrhotic patients; however, the contribution of liver in this process has not been clarified. To estimate the effect of BCAA on glucose metabolism in liver, we evaluated the mRNA expression levels of glucose-sensing apparatus genes in HepG2 cells and in rat liver after oral administration of BCAA. HepG2 cells were cultured in low glucose (100 mg/dl) or high glucose (400 mg/dl) in the absence or presence of BCAA. The mRNA expression levels and protein levels of GLUT2 and liver-type glucokinase (L-GK) were estimated using RT-PCR and immunoblotting. The expression levels of transcriptional factors, including SREBP-1c, ChREBP, PPAR-γm and LXRα, were estimated. The mRNA expression levels of transcriptional factors, glycogen synthase, and genes involved in gluconeogenesis were evaluated in rat liver at 3 h after the administration of BCAA. BCAA accelerated the expression of GLUT2 and L-GK in HepG2 cells in high glucose. Expression levels of ChREBP, SREBP-1c, and LXRα were also increased in this condition. BCAA administration enhanced the mRNA expression levels of L-GK, SREBP-1c, and LXRα and suppressed the expression levels of G-6-Pase in rat liver, without affecting the expression levels of glycogen synthase or serum glucose concentrations. BCAA administration enhanced the bioactivity of the glucose-sensing apparatus, probably via the activation of a transcriptional mechanism, suggesting that these amino acids may improve glucose metabolism through the accelerated utility of glucose and glucose-6-phosphate in the liver.

Branched-chain amino acids in liver disease: new aspects of long known phenomena

PURPOSE OF REVIEW

To provide an overview of findings on the role of branched-chain amino acids (BCAAs) in the pathophysiology, pathobiochemistry, and treatment of liver cirrhosis and its complications that have been published since or were not included in the last review on this topic in 2007 in this journal.

RECENT FINDINGS

There has been continued interest in the potential of oral BCAA supplements in improving energy metabolism, nitrogen metabolism, carbohydrate metabolism, insulin resistance, severity of liver disease, serum albumin levels, quality of serum albumin, or postoperative complication rates. Unfortunately, many trials suffer from lacking or inadequate controls or small sample size. In a fine example of scientific perseverance, Dutch researchers uncovered the long-known phenomenon of ingested blood being highly comagenic in patients with cirrhosis to be due to the low biologic value of blood protein. The absence of isoleucine and the abundance of leucine in the hemoglobin molecule by way of BCAA antagonism leads to impaired protein synthesis and azotemia paving the way for hepatic encephalopathy.

SUMMARY

Recognizing hypoisoleucinemia and BCAA antagonism following gastrointestinal bleeding, and its successful treatment by isoleucine infusion has advanced our understanding of the role of BCAA in liver cirrhosis.

Effect of a late evening snack using branched-chain amino acid-enriched nutrients in patients undergoing hepatic arterial infusion chemotherapy for advanced hepatocellular carcinoma

AIM

A late evening snack (LES) is recommended for protein-energy malnutrition in patients with liver cirrhosis. This study investigated energy metabolism in cirrhotic patients with hepatocellular carcinoma (HCC) and the effects of LES using a branched-chain amino acid (BCAA)-enriched nutrient in cirrhotic patients with advanced HCC undergoing hepatic arterial infusion chemotherapy (HAIC).

METHODS

Energy metabolism was measured using indirect calorimetry for 10 cirrhotic patients without HCC and 36 patients with various stages of HCC. Next, in 23 cirrhotic patients with advanced HCC undergoing HAIC, 13 patients received LES (LES group), and 10 patients received ordinary food (control group). Changes in energy metabolism and glucose tolerance were examined using indirect calorimetry and 75-g oral glucose tolerance test (OGTT) before and after 1 cycle of treatment.

RESULTS

Non-protein respiratory quotient (npRQ) was significantly lower in patients with advanced HCC than in cirrhotic patients without HCC, or in patients with early-stage HCC. In cirrhotic patients with advanced HCC undergoing HAIC, npRQ, BCAA/tyrosine ratio (BTR), and prealbumin and ALT levels were significantly improved in the LES group, but not in controls. In addition, area under the concentration curve for glucose (AUC glucose) tended to be improved in the LES group.

CONCLUSIONS

LES using BCAA-enriched nutrients appears to improve energy metabolism and glucose tolerance in cirrhotic patients with advanced HCC undergoing HAIC.

Importance of hepatitis C virus-associated insulin resistance: Therapeutic strategies for insulin sensitization

Insulin resistance is one of the pathological features in patients with hepatitis C virus (HCV) infection. Generally, persistence of insulin resistance leads to an increase in the risk of life-threatening complications such as cardiovascular diseases. However, these complications are not major causes of death in patients with HCV-associated insulin resistance. Indeed, insulin resistance plays a crucial role in the development of various complications and events associated with HCV infection. Mounting evidence indicates that HCV-associated insulin resistance may cause (1) hepatic steatosis; (2) resistance to anti-viral treatment; (3) hepatic fibrosis and esophageal varices; (4) hepatocarcinogenesis and proliferation of hepatocellular carcinoma; and (5) extrahepatic manifestations. Thus, HCV-associated insulin resistance is a therapeutic target at any stage of HCV infection. Although the risk of insulin resistance in HCV-infected patients has been documented, therapeutic guidelines for preventing the distinctive complications of HCV-associated insulin resistance have not yet been established. In addition, mechanisms for the development of HCV-associated insulin resistance differ from lifestyle-associated insulin resistance. In order to ameliorate HCV-associated insulin resistance and its complications, the efficacy of the following interventions is discussed: a late evening snack, coffee consumption, dietary iron restriction, phlebotomy, and zinc supplements. Little is known regarding the effect of anti-diabetic agents on HCV infection, however, a possible association between use of exogenous insulin or a sulfonylurea agent and the development of HCC has recently been reported. On the other hand, insulin-sensitizing agents are reported to improve sustained virologic response rates. In this review, we summarize distinctive complications of, and therapeutic strategies for, HCV-associated insulin resistance. Furthermore, we discuss supplementation with branched-chain amino acids as a unique insulin-sensitizing strategy for patients with HCV-associated insulin resistance.

Systemic abnormalities in liver disease

Systemic abnormalities often occur in patients with liver disease. In particular, cardiopulmonary or renal diseases accompanied by advanced liver disease can be serious and may determine the quality of life and prognosis of patients. Therefore, both hepatologists and non-hepatologists should pay attention to such abnormalities in the management of patients with liver diseases.