Branched-chain amino acids suppress insulin-resistance-based hepatocarcinogenesis in obese diabetic rats

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.

Effect of perioperative branched chain amino acids supplementation in liver cancer patients undergoing surgical intervention: A systematic review

BACKGROUND

Branched chain amino acid (BCAA) supplementation has been associated with favourable outcomes in liver malignancies requiring definitive resection or liver transplantation. Currently, there are no updated systematic reviews evaluating the efficacy of perioperative BCAA supplementation in patients undergoing surgery for liver cancer.

AIM

To evaluate the efficacy of perioperative BCAA supplementation in patients undergoing surgery for liver cancer.

METHODS

A systematic review of randomized control trials and observational studies was conducted on PubMed, Embase, Cochrane Library, Scopus, and Web of Science to evaluate the effect of perioperative BCAA supplementation compared to standard in-hospital diet, in liver cancer patients undergoing surgery. Clinical outcomes were extracted, and a meta-analysis was performed on relevant outcomes.

RESULTS

16 studies including 1389 patients were included. Perioperative BCAA administration was associated with reduced postoperative infection [risk ratio (RR) = 0.58 95% confidence intervals (CI): 0.39 to 0.84, P = 0.005] and ascites [RR = 0.57 (95%CI: 0.38 to 0.85), P = 0.005]. There was also a reduction in length of hospital stay (LOS) [weighted mean difference (WMD) = -3.03 d (95%CI: -5.49 to -0.57), P = 0.02] and increase in body weight [WMD = 1.98 kg (95%CI: 0.35 to 3.61, P = 0.02]. No significant differences were found in mortality, cancer recurrence and overall survival. No significant safety concerns were identified.

CONCLUSION

Perioperative BCAA administration is efficacious in reducing postoperative infection, ascites, LOS, and increases body weight in liver cancer patients undergoing surgical resection.

The mechanism of branched-chain amino acid transferases in different diseases: Research progress and future prospects

It is well known that the enzyme catalyzes the first step of branched-chain amino acid (BCAA) catabolism is branched-chain amino transferase (BCAT), which is involved in the synthesis and degradation of leucine, isoleucine and valine. There are two main subtypes of human branched chain amino transferase (hBCAT), including cytoplasmic BCAT (BCAT1) and mitochondrial BCAT (BCAT2). In recent years, the role of BCAT in tumors has attracted the attention of scientists, and there have been continuous research reports that BCAT plays a role in the tumor, Alzheimer’s disease, myeloid leukaemia and other diseases. It plays a significant role in the growth and development of diseases, and new discoveries about this gene in some diseases are made every year. BCAT usually promotes cancer proliferation and invasion by activating the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin pathway and activating Wnt/β-catenin signal transduction. This article reviews the role and mechanism of BCAT in different diseases, as well as the recent biomedical research progress. This review aims to make a comprehensive summary of the role and mechanism of BCAT in different diseases and to provide new research ideas for the treatment, prognosis and prevention of certain diseases.

DeepHisCoM: deep learning pathway analysis using hierarchical structural component models

Many statistical methods for pathway analysis have been used to identify pathways associated with the disease along with biological factors such as genes and proteins. However, most pathway analysis methods neglect the complex nonlinear relationship between biological factors and pathways. In this study, we propose a Deep-learning pathway analysis using Hierarchical structured CoMponent models (DeepHisCoM) that utilize deep learning to consider a nonlinear complex contribution of biological factors to pathways by constructing a multilayered model which accounts for hierarchical biological structure. Through simulation studies, DeepHisCoM was shown to have a higher power in the nonlinear pathway effect and comparable power for the linear pathway effect when compared to the conventional pathway methods. Application to hepatocellular carcinoma (HCC) omics datasets, including metabolomic, transcriptomic and metagenomic datasets, demonstrated that DeepHisCoM successfully identified three well-known pathways that are highly associated with HCC, such as lysine degradation, valine, leucine and isoleucine biosynthesis and phenylalanine, tyrosine and tryptophan. Application to the coronavirus disease-2019 (COVID-19) single-nucleotide polymorphism (SNP) dataset also showed that DeepHisCoM identified four pathways that are highly associated with the severity of COVID-19, such as mitogen-activated protein kinase (MAPK) signaling pathway, gonadotropin-releasing hormone (GnRH) signaling pathway, hypertrophic cardiomyopathy and dilated cardiomyopathy. Codes are available at https://github.com/chanwoo-park-official/DeepHisCoM.

Branched-chain amino acids protect the liver from cirrhotic injury via suppression of activation of lipopolysaccharide-binding protein, toll-like receptor 4, and signal transducer and activator of transcription 3, as well as Enterococcus faecalis translocation

OBJECTIVES

Branched-chain amino acids (BCAAs) are used as nutritional support and for improving prognosis in liver cirrhosis. Here we investigate the molecular mechanisms of BCAA treatment and liver damage focused on pathways related to lipopolysaccharide-binding protein (LBP).

METHODS

Serum LBP levels were measured in cirrhotic patients and in cirrhotic rats treated with BCAA to examine the correlation between liver function and survival. In cirrhotic rats, liver damage, Enterococcus faecalis translocation, serum capsular polysaccharide, and intestinal tight junction levels were assessed. Damaged HepG2 cells were cultured with BCAA-supplemented, BCAA-deficient, or control amino acid medium, followed by examination of LBP expression.

RESULTS

Serum LBP levels were significantly increased in deceased patients individuals with liver cirrhosis. The survival rate in patients with lower serum LBP (<3.48 μg/mL) was significantly improved. In BCAA-treated rat liver samples, protein expression of LBP, toll-like receptor 4 (TLR4), and phosphorylated signal transduction and activator of transcription 3 (STAT3) were significantly reduced. Also in BCAA-treated rats, intestinal zonula occludens gene expression was increased, whereas hepatic translocation of E. faecalis and serum capsular polysaccharide levels were reduced. In damaged HepG2 cells, lipopolysaccharide-induced elevation of LBP expression was rapidly and strongly repressed in BCAA-enriched medium.

CONCLUSIONS

Serum LBP level is a prognostic biomarker in liver cirrhosis. BCAA treatment reduced translocation of E. faecalis through intestinal tight junction recovery and reduced LBP expression in the liver, which repressed activation of LBP, toll-like receptor 4, and signal transduction and activator of transcription 3. Our findings suggest that BCAA supplementation protects the liver from damage via multiple pathways.

Effects of branched-chain amino acids on postoperative tumor recurrence in patients undergoing curative resection for hepatocellular carcinoma: A randomized clinical trial

BACKGROUND/PURPOSE

No effective postoperative adjuvant therapies have been established for patients with hepatocellular carcinoma (HCC). The aim of this study was to investigate the effect of oral administration of branched-chain amino acids (BCAA) on the recurrence-free survival (RFS) after hepatic resection in HCC patients.

METHODS

In this randomized clinical trial, HCC patients undergoing curative resections were randomly assigned in a 1:1 ratio to the BCAA group or surgery-alone group. The BCAA group received BCAA (Livact^® ) for up to 4 years. The primary endpoint was RFS. The secondary endpoint was overall survival (OS). Multivariate analysis was performed to detect the clinical characteristics significantly associated with RFS.

RESULTS

Between January 2010 and October 2014, 156 patients (75 in BCAA group and 81 in surgery-alone group) were enrolled in the study. Of these, two patients were excluded from the efficacy analysis. Comparison of the survival curves by the log rank test demonstrated no significant difference in the RFS (P = .579) or OS (P = .268) between the BCAA and the control group. Multivariate analysis revealed that the RFS was significantly associated with age and number of tumors. A beneficial effect of BCAA on the RFS was found in patients younger than 72 years old with a HbA1c level of < 6.4%.

CONCLUSIONS

Oral BCAA supplementation could not reduce the risk of recurrence after hepatic resection in HCC patients; however, the results suggested that BCAA supplementation may be beneficial for selected patients who were younger and had mildly impaired glucose tolerance.

Pre-Operative vs. Peri-Operative Nutrition Supplementation in Hepatic Resection for Cancer: A Systematic Review

Despite improvements in safety of hepatic resection post-operative complications occur in up to a half of patients. A systematic review was undertaken to compare the effect of pre-operative and peri-operative nutritional supplementation on post-operative outcomes in patients undergoing hepatic resection for malignancy. Included studies were identified through a search of PubMed (1966 to November 2016), Embase (1947 to November 2016) and the Cochrane Library (1993 to November 2016). Eleven studies involving a total of 725 patients were included in this systematic review. BCAA supplementation in the pre-operative and peri-operative period was reported to reduce the overall complication rate by 26.9% (P = 0.01) in one cohort study while pre-operative immunonutrition was shown to reduce post-operative ascites by 25.4% (P =0.012) in another cohort study without affecting the overall complication rate. Four further studies on enteral supplementation failed to show a benefit with regards to post-operative complications. Post-operative mortality was unaffected by pre-operative and peri-operative BCAA. Both pre-operative and peri-operative nutritional supplementation have shown promising results regarding the post-operative course of patients undergoing hepatic resection for malignancy. No randomized controlled study exists directly comparing pre-operative and peri-operative nutrition and this needs to be focused on in future research.

Ezetimibe suppresses development of liver tumors by inhibiting angiogenesis in mice fed a high-fat diet

Nonalcoholic steatohepatitis (NASH) is a common cause of liver cirrhosis and hepatocellular carcinoma (HCC). However, effective therapeutic strategies for preventing and treating NASH‐mediated liver cirrhosis and HCC are lacking. Cholesterol is closely associated with vascular endothelial growth factor (VEGF), a key factor that promotes HCC. Recent reports have demonstrated that statins could prevent HCC development. In contrast, we have little information on ezetimibe, an inhibitor of cholesterol absorption, in regards to the prevention of NASH‐related liver cirrhosis and HCC. In the present study, a steatohepatitis‐related HCC model, hepatocyte‐specific phosphatase and tensin homolog (Pten)‐deficient (Pten^Δhep) mice were fed a high‐fat (HF) diet with/without ezetimibe. In the standard‐diet group, ezetimibe did not reduce the development of liver tumors in Pten^Δhep mice, in which the increase of serum cholesterol levels was mild. Feeding of a HF diet increased serum cholesterol levels markedly and subsequently increased serum levels of VEGF, a crucial component of angiogenesis. The HF diet increased the number of VEGF‐positive cells and vascular endothelial cells in the tumors of Pten^Δhep mice. Kupffer cells, macrophages in the liver, increased VEGF expression in response to fat overload. Ezetimibe treatment lowered cholesterol levels and these angiogenetic processes. As a result, ezetimibe also suppressed inflammation, liver fibrosis and tumor growth in Pten^Δhep mice on the HF diet. Tumor cells were highly proliferative with HF‐diet feeding, which was inhibited by ezetimibe. In conclusion, ezetimibe suppressed development of liver tumors by inhibiting angiogenesis in Pten^Δhep mice with hypercholesterolemia.

Chicken breast muscle hydrolysates ameliorate acute alcohol-induced liver injury in mice through alcohol dehydrogenase (ADH) activation and oxidative stress reduction

In this study, the ameliorative effect of chicken breast muscle hydrolysates (CBMHs) against acute alcohol-induced liver injury was investigated and its probable mechanism was further elucidated. In vitro studies clearly showed that CBMHs are able to activate alcohol metabolic enzymes (i.e. alcohol dehydrogenase, ADH) in an exponential manner. Meanwhile, an in vivo experiment on male NIH mice indicated that the oral administration of CBMHs (150, 300 and 600 mg per kg bw) 30 min prior to acute alcohol ingestion could significantly promote alcohol metabolism as revealed by the reduced duration of the loss of righting reflex (LORR) and the enhanced activity of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) in the liver, the latter accelerating alcohol oxidation and therefore the decreased blood alcohol concentration (BAC) level. Pretreatment with CBMHs significantly decreased the elevations of serum aspartate transaminase (AST) and alanine transaminase (ALT) after alcohol administration. CBMHs could also retard lipid peroxidation as revealed by the suppressed malondialdehyde (MDA) level and simultaneously enhance the activities of superoxide dismutase (SOD) in liver tissue. Furthermore, increased histological damage and higher (p < 0.05) hepatic triglyceride (TG) contents in acute alcoholic-diet fed mice were also reduced (p < 0.05) by supplementing with CBMHs. These benefits clearly suggested that CBMHs could be a potential nutraceutical to facilitate alcohol metabolism and prevent or ameliorate early liver injury induced by acute alcohol exposure.

Leucine deprivation inhibits proliferation and induces apoptosis of human breast cancer cells via fatty acid synthase

Substantial studies on fatty acid synthase (FASN) have focused on its role in regulating lipid metabolism and researchers have a great interest in treating cancer with dietary manipulation of amino acids. In the current study, we found that leucine deprivation caused the FASN-dependent anticancer effect. Here we showed that leucine deprivation inhibited cell proliferation and induced apoptosis of MDA-MB-231 and MCF-7 breast cancer cells. In an in vivo tumor xenograft model, the leucine-free diet suppressed the growth of human breast cancer tumors and triggered widespread apoptosis of the cancer cells. Further study indicated that leucine deprivation decreased expression of lipogenic gene FASN in vitro and in vivo. Over-expression of FASN or supplementation of palmitic acid (the product of FASN action) blocked the effects of leucine deprivation on cell proliferation and apoptosis in vitro and in vivo. Moreover, leucine deprivation suppressed the FASN expression via regulating general control non-derepressible (GCN)2 and sterol regulatory element-binding protein 1C (SREBP1C). Taken together, our study represents proof of principle that anticancer effects can be obtained with strategies to deprive tumors of leucine via suppressing FASN expression, which provides important insights in prevention of breast cancer via metabolic intervention.

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.

Relation of the IGF/IGF1R system to autophagy in colitis and colorectal cancer

Metabolic syndrome (MetS), as a chronic inflammatory disorder has a potential role in the development of inflammatory and cancerous complications of the colonic tissue. The interaction of DNA damage and inflammation is affected by the insulin-like growth factor 1 receptor (IGF1R) signaling pathway. The IGF1R pathway has been reported to regulate autophagy, as well, but sometimes through a bidirectional context. Targeting the IGF1R-autophagy crosstalk could represent a promising strategy for the development of new antiinflammatory and anticancer therapies, and may help for subjects suffering from MetS who are at increased risk of colorectal cancer. However, therapeutic responses to targeted therapies are often shortlived, since a signaling crosstalk of IGF1R with other receptor tyrosine kinases or autophagy exists, leading to acquired cellular resistance to therapy. From a pharmacological point of view, it is attractive to speculate that synergistic benefits could be achieved by inhibition of one of the key effectors of the IGF1R pathway, in parallel with the pharmacological stimulation of the autophagy machinery, but cautiousness is also required, because pharmacologic IGF1R modulation can initiate additional, sometimes unfavorable biologic effects.

Branched-chain amino acids prevent hepatic fibrosis and development of hepatocellular carcinoma in a non-alcoholic steatohepatitis mouse model

Oral supplementation with branched-chain amino acids (BCAA; leucine, isoleucine, and valine) in patients with liver cirrhosis potentially suppresses the incidence of hepatocellular carcinoma (HCC) and improves event-free survival. However, the detailed mechanisms of BCAA action have not been fully elucidated. BCAA were administered to atherogenic and high-fat (Ath+HF) diet-induced nonalcoholic steatohepatitis (NASH) model mice. Liver histology, tumor incidence, and gene expression profiles were evaluated. Ath+HF diet mice developed hepatic tumors at a high frequency at 68 weeks. BCAA supplementation significantly improved hepatic steatosis, inflammation, fibrosis, and tumors in Ath+HF mice at 68 weeks. GeneChip analysis demonstrated the significant resolution of pro-fibrotic gene expression by BCAA supplementation. The anti-fibrotic effect of BCAA was confirmed further using platelet-derived growth factor C transgenic mice, which develop hepatic fibrosis and tumors. In vitro, BCAA restored the transforming growth factor (TGF)-β1-stimulated expression of pro-fibrotic genes in hepatic stellate cells (HSC). In hepatocytes, BCAA restored TGF-β1-induced apoptosis, lipogenesis, and Wnt/β-Catenin signaling, and inhibited the transformation of WB-F344 rat liver epithelial stem-like cells. BCAA repressed the promoter activity of TGFβ1R1 by inhibiting the expression of the transcription factor NFY and histone acetyltransferase p300. Interestingly, the inhibitory effect of BCAA on TGF-β1 signaling was mTORC1 activity-dependent, suggesting the presence of negative feedback regulation from mTORC1 to TGF-β1 signaling. Thus, BCAA induce an anti-fibrotic effect in HSC, prevent apoptosis in hepatocytes, and decrease the incidence of HCC; therefore, BCAA supplementation would be beneficial for patients with advanced liver fibrosis with a high risk of HCC.

Long-term effects intensive medical therapy on the development and progression of subclinical atherosclerosis and the metabolic syndrome in Chinese patients with type 2 diabetes mellitus

BACKGROUND

Few studies have investigated the progression of subclinical atherosclerosis and metabolic syndrome (MetS) in Chinese patients with type 2 diabetes mellitus (T2DM). This study was to compare the long-term effects of intensive medical therapy on the development and progression of subclinical atherosclerosis and MetS in Chinese T2DM patients with that of a conventional treatment regimen.

METHODS

A total of 316 T2DM patients were randomized to receive conventional pharmacological treatment or intensive medical therapy, consisting of diet and exercise counseling, from 2002 to 2014 at our hospital in Changsha, China. Clinical indicators of subclinical atherosclerosis and MetS were evaluated over the 12-year follow-up period. A χ analysis or t tests was used to compare the data between the 2 groups. Risk factors for subclinical atherosclerosis were identified using Cox proportional hazard models.

RESULTS

The incidence of subclinical atherosclerosis increased in both groups over time, and did not differ significantly between the 2 groups at the end of the study. However, after 6 years of treatment, the risk of subclinical atherosclerosis was significantly lower in the intensive medical therapy group, based on intima-media thickness (IMT) measurements, compared with that in the conventional treatment (44.2% vs. 69.7%; P < 0.01). Age, creatinine, and IMT of the common iliac artery were significantly associated with subclinical atherosclerosis. Although the indicators of MetS did not differ significantly at the end of study, the success rate for the management of MetS in the intensive medical therapy group was significantly higher than that in the conventional treatment group in 2006, 2008, 2010, and 2012.

CONCLUSIONS

The incidence of atherosclerosis in the intensive medical therapy group was significantly lower than that in the conventional treatment group from 2006 to 2010 (P < 0.05), and the incidence of MetS in the intensive medical therapy group was significantly higher than that in the conventional treatment group from 2006 to 2012. Kaplan-Meier estimations showed that the risk of subclinical atherosclerosis in the intensive medical therapy group was significantly lower than that in the conventional treatment group (P < 0.001), whereas the risk of MetS was not significantly different between the treatment groups (P > 0.05).

Supportive therapies for prevention of hepatocellular carcinoma recurrence and preservation of liver function

Hepatocellular carcinoma (HCC) is one of the deadliest cancers in the world and is associated with a high risk of recurrence. The development of a wide range of new therapies is therefore essential. In this study, from the perspective of supportive therapy for the prevention of HCC recurrence and preservation of liver function in HCC patients, we surveyed a variety of different therapeutic agents. We show that branched chain amino acids (BCAA) supplementation and late evening snack with BCAA, strategies that address issues of protein-energy malnutrition, are important for liver cirrhotic patients with HCC. For chemoprevention of HCC recurrence, we show that viral control after radical treatment is important. We also reviewed the therapeutic potential of antiviral drugs, sorafenib, peretinoin, iron chelators. Sorafenib is a kinase inhibitor and a standard therapy in the treatment of advanced HCC. Peretinoin is a vitamin A-like molecule that targets the retinoid nuclear receptor to induce apoptosis and inhibit tumor growth in HCC cells. Iron chelators, such as deferoxamine and deferasirox, act to prevent cancer cell growth. These chelators may have potential as combination therapies in conjunction with peretinoin. Finally, we review the potential inhibitory effect of bone marrow cells on hepatocarcinogenesis.

Effect of branched-chain amino acid supplementation on functional liver regeneration in patients undergoing portal vein embolization and sequential hepatectomy: a randomized controlled trial

BACKGROUND

Portal vein embolization (PVE) can decrease the resection ratio for major hepatectomy. (99m)Tc-galactosyl human serum albumin (GSA) scintigraphy is useful for evaluating quantitative functional liver volume. Branched chain amino acids (BCAAs) modulate liver function and regeneration. We analyzed the effects of BCAAs, in terms of liver function and regeneration after PVE, in combination with major hepatectomy.

METHODS

This randomized controlled trial was conducted for patients receiving PVE through to complete hepatectomy from September, 2011 to June, 2013. BCAA granules were added two times a day to a conventional diet in the BCAA administration group (BCAA group). The primary end point was functional liver regeneration of the future remnant liver after PVE followed by hepatic resection. Functional liver regeneration was assessed by the liver uptake value obtained from (99m)Tc-GSA scintigraphy single-photon-emission computed tomography/computed tomography fusion images. The secondary end points were volumetric liver regeneration and changes in liver function and laboratory data.

RESULTS

A BCAA group (n = 13) and a non-BCAA group (control group; n = 15) were included. The primary end point was partially met: the liver uptake value significantly increased in the BCAA group compared with the control group 6 months after hepatic resection (266.7% vs 77.6%, P = 0.04) and marginally increased after PVE (43.8% vs 17.4%, P = 0.079). Following PVE, the increment of the uptake ratio of the liver to the liver plus heart at 15 min was significantly less in the BCAA group than in the control group (0.0 and 0.01, P = 0.023).

CONCLUSIONS

BCAA supplementation improved functional liver regeneration and function in patients undergoing PVE followed by major hepatic resection.

Liver Cirrhosis: Evaluation, Nutritional Status, and Prognosis

The liver is the major organ for the metabolism of three major nutrients: protein, fat, and carbohydrate. Chronic hepatitis C virus infection is the major cause of chronic liver disease. Liver cirrhosis (LC) results from different mechanisms of liver injury that lead to necroinflammation and fibrosis. LC has been seen to be not a single disease entity but one that can be graded into distinct clinical stages related to clinical outcome. Several noninvasive methods have been developed for assessing liver fibrosis and these methods have been used for predicting prognosis in patients with LC. On the other hand, subjects with LC often have protein-energy malnutrition (PEM) and poor physical activity. These conditions often result in sarcopenia, which is the loss of skeletal muscle volume and increased muscle weakness. Recent studies have demonstrated that PEM and sarcopenia are predictive factors for poorer survival in patients with LC. Based on these backgrounds, several methods for evaluating nutritional status in patients with chronic liver disease have been developed and they have been preferably used in the clinical field practice. In this review, we will summarize the current knowledge in the field of LC from the viewpoints of diagnostic method, nutritional status, and clinical outcomes.

Excess visceral adiposity induces alterations in mitochondrial function and energy metabolism in esophageal adenocarcinoma

BACKGROUND

Visceral obesity has a strong association with both the incidence and mortality of esophageal adenocarcinoma (EAC). Alterations in mitochondrial function and energy metabolism is an emerging hallmark of cancer, however, the potential role that obesity plays in driving these alterations in EAC is currently unknown.

METHODS

Adipose conditioned media (ACM) was prepared from visceral adipose tissue taken from computed tomography-determined viscerally-obese and non-obese EAC patients. Mitochondrial function in EAC cell lines was assessed using fluorescent probes, mitochondrial gene expression was assessed using qPCR-based gene arrays and intracellular ATP levels were determined using a luminescence-based kit. Glycolysis and oxidative phosphophorylation was measured using Seahorse XF technology and metabolomic analysis was performed using 1H NMR. Expression of metabolic markers was assessed in EAC tumor biopsies by qPCR.

RESULTS

ACM from obese EAC patients significantly increased mitochondrial mass and mitochondrial membrane potential in EAC cells, which was significantly associated with visceral fat area, and was coupled with a significant decrease in reactive oxygen species. This mitochondrial dysfunction was accompanied by altered expression of 19 mitochondrial-associated genes and significantly reduced intracellular ATP levels. ACM from obese EAC patients induced a metabolic shift to glycolysis in EAC cells, which was coupled with significantly increased sensitivity to the glycolytic inhibitor 2-deoxyglucose. Metabolomic profiling demonstrated an altered glycolysis and amino acid-related signature in ACM from obese patients. In EAC tumors, expression of the glycolytic marker PKM2 was significantly positively associated with obesity.

CONCLUSION

This study demonstrates for the first time that ACM from viscerally-obese EAC patients elicits an altered metabolic profile and can drive mitochondrial dysfunction and altered energy metabolism in EAC cells in vitro. In vivo, in EAC patient tumors, expression of the glycolytic enzyme PKM2 is positively associated with obesity.

Albumin suppresses human hepatocellular carcinoma proliferation and the cell cycle

Many investigations have revealed that a low recurrence rate of hepatocellular carcinoma (HCC) is associated with high serum albumin levels in patients; therefore, high levels of serum albumin are a major indicator of a favorable prognosis. However, the mechanism inhibiting the proliferation of HCC has not yet been elucidated, so we investigated the effect of serum albumin on HCC cell proliferation. Hep3B was cultured in MEM with no serum or containing 5 g/dL human albumin. As control samples, Prionex was added to generate the same osmotic pressure as albumin. After 24-h incubation, the expressions of α-fetoprotein (AFP), p53, p21, and p57 were evaluated with real-time PCR using total RNA extracted from the liver. Protein expressions and the phosphorylation of Rb (retinoblastoma) were determined by Western blot analysis using total protein extracted from the liver. For flow cytometric analysis of the cell cycle, FACS analysis was performed. The percentages of cell cycle distribution were evaluated by PI staining, and all samples were analyzed employing FACScalibur (BD) with appropriate software (ModFit LT; BD). The cell proliferation assay was performed by counting cells with using a Scepter handy automated cell counter (Millipore). The mRNA levels of AFP relative to Alb(−): Alb(−), Alb(+), and Prionex, were 1, 0.7 ± 0.2 (p < 0.001 for Alb(−)), and 1 ± 0.3, respectively. The mRNA levels of p21 were 1, 1.58 ± 0.4 (p = 0.007 for Alb(−) and p = 0.004 for Prionex), and 0.8 ± 0.2, respectively. The mRNA levels of p57 were 1, 4.4 ± 1.4 (p = 0.002 for Alb(−) and Prionex), and 1.0 ± 0.1, respectively. The protein expression levels of Rb were similar in all culture media. The phosphorylation of P807/811 and P780 of Rb protein was reduced in Alb(+). More cells in the G0/G1 phase and fewer cells in S and G2/M phases were obtained in Alb(+) than in Alb(−) (G0/G1: 60.9%, 67.7%, 61.5%; G2/M: 16.5%, 13.1%, 15.6%; S: 22.6%, 19.2%, 23.0%, Alb(−), Alb(+), Prionex, respectively). The same results were obtained in HepG2. Cell proliferation was inhibited in 5 g/dL albumin medium in both HepG2 cells and Hep3B cells in 24 h culture by counting cell numbers. The presence of albumin in serum reduces the phosphorylation of Rb proteins and enhances the expression of p21 and p57, following an increase in the G0/G1 cell population, and suppresses cell proliferation. These results suggest that albumin itself suppresses the proliferation of hepatocellular carcinoma.

Oral supplementation with branched-chain amino acid granules prevents hepatocarcinogenesis in patients with hepatitis C-related cirrhosis: A propensity score analysis

AIM

It has been reported that branched-chain amino acids (BCAA) supplementation can improve nutritional status and reduce liver-related complications in patients with decompensated cirrhosis. BCAA supplementation reportedly reduces the incidence of hepatocellular carcinoma (HCC) in obese cirrhotic patients infected with hepatitis C virus (HCV). We investigated the effects of oral supplementation with BCAA granules on hepatocarcinogenesis in patients with HCV-related cirrhosis using propensity score matching.

METHODS

A total of 60 patients with HCV-related cirrhosis and without history of HCC who were selected by one-to-one matching of propensity scores: 30 patients receiving 12 g/day of BCAA granules for 3 months or more (BCAA group) and 30 being observed without BCAA supplementation (control group). The impact of BCAA supplementation was analyzed on the incidence of HCC.

RESULTS

The 3- and 5-year rates of HCC development were 13.7% and 13.7% in the BCAA group and 35.1% and 44.5% in the control group, respectively. The BCAA group had a significantly lower rate of HCC than the control group (P = 0.032). Multivariate analysis for factors that were associated with hepatocarcinogenesis indicated that BCAA supplementation was independently associated with a reduced incidence of HCC (hazard ratio 0.131; 95% confidence interval, 0.032-0.530; P = 0.004) along with sex and serum α-fetoprotein. Obesity (body mass index, ≥25 kg/m(2) ) was not significantly associated with an increased incidence of HCC.

CONCLUSION

Oral supplementation with BCAA granules is associated with a reduced incidence of HCC in patients with HCV-related cirrhosis regardless of the presence of obesity based on the propensity score analysis.

Clinical significance of therapy using branched-chain amino acid granules in patients with liver cirrhosis and hepatocellular carcinoma

The liver is the major organ for the metabolism of protein, fat and carbohydrate. A nutritional approach is required in the treatment of cirrhosis, which is frequently complicated with protein-energy malnutrition. Several advanced treatment approaches for hepatocellular carcinoma (HCC) have been established in the past decade. HCC is often complicated by cirrhosis, so treatment of the underlying liver diseases is also necessary to improve the prognosis. Branched-chain amino acid (BCAA) granules were developed originally for the treatment of hypoalbuminemia associated with decompensated cirrhosis. However, subsequent studies found various other pharmacological actions of this agent. We review the clinical significance of therapy using BCAA granules in patients receiving different treatment approaches for cirrhosis and HCC based on the published work as well as our own data.

Branched chain amino acid suppresses hepatocellular cancer stem cells through the activation of mammalian target of rapamycin

Differentiation of cancer stem cells (CSCs) into cancer cells causes increased sensitivity to chemotherapeutic agents. Although inhibition of mammalian target of rapamycin (mTOR) leads to CSC survival, the effect of branched chain amino acids (BCAAs), an mTOR complex 1 (mTORC1) activator remains unknown. In this study, we examined the effects of BCAA on hepatocellular carcinoma (HCC) cells expressing a hepatic CSC marker, EpCAM. We examined the effects of BCAA and/or 5-fluorouracil (FU) on expression of EpCAM and other CSC-related markers, as well as cell proliferation in HCC cells and in a xenograft mouse model. We also characterized CSC-related and mTOR signal-related molecule expression and tumorigenicity in HCC cells with knockdown of Rictor or Raptor, or overexpression of constitutively active rheb (caRheb). mTOR signal-related molecule expression was also examined in BCAA-treated HCC cells. In-vitro BCAA reduced the frequency of EpCAM-positive cells and improved sensitivity to the anti-proliferative effect of 5-FU. Combined 5-FU and BCAA provided better antitumor efficacy than 5-FU alone in the xenograft model. Stimulation with high doses of BCAA activated mTORC1. Knockdown and overexpression experiments revealed that inhibition of mTOR complex 2 (mTORC2) or activation of mTORC1 led to decreased EpCAM expression and little or no tumorigenicity. BCAA may enhance the sensitivity to chemotherapy by reducing the population of cscs via the mTOR pathway. This result suggests the utility of BCAA in liver cancer therapy.

Pharmaceutical and nutraceutical approaches for preventing liver carcinogenesis: chemoprevention of hepatocellular carcinoma using acyclic retinoid and branched-chain amino acids

The poor prognosis for patients with hepatocellular carcinoma (HCC) is associated with its high rate of recurrence in the cirrhotic liver. Therefore, more effective strategies need to be urgently developed for the chemoprevention of this malignancy. The malfunction of retinoid X receptor α, a retinoid receptor, due to phosphorylation by Ras/mitogen-activated protein kinase is closely associated with liver carcinogenesis and may be a promising target for HCC chemoprevention. Acyclic retinoid (ACR), a synthetic retinoid, can prevent HCC development by inhibiting retinoid X receptor α phosphorylation and improve the prognosis for this malignancy. Supplementation with branched-chain amino acids (BCAA), which are used to improve protein malnutrition in patients with liver cirrhosis, can also reduce the risk of HCC in obese cirrhotic patients. In experimental studies, both ACR and BCAA exert suppressive effects on HCC development and the growth of HCC cells. In particular, combined treatment with ACR and BCAA cooperatively inhibits the growth of HCC cells. Furthermore, ACR and BCAA inhibit liver tumorigenesis associated with obesity and diabetes, both of which are critical risk factors for HCC development. These findings suggest that pharmaceutical and nutraceutical approaches using ACR and BCAA may be promising strategies for preventing HCC and improving the prognosis of this malignancy.

Direct renin inhibitor, aliskiren, attenuates the progression of non-alcoholic steatohepatitis in the rat model

AIM

Renin is a rate-limiting enzyme of the renin-angiotensin system (RAS), and several reports have shown that renin plays an important role in several pathological processes. Although RAS is known to play a pivotal role in the progression of non-alcoholic steatohepatitis (NASH), the role of renin is still obscure. The aim of the current study was to examine the effect of the clinically used direct renin inhibitor (DRI), aliskiren, on the progression of NASH in a rat model.

METHODS

The effects of DRI on the choline-deficient L-amino acid-defined (CDAA) diet-induced rat NASH model was examined in conjunction with the activated hepatic stellate cells (Ac-HSC) and neovascularization, both of which are known to play important roles in liver fibrosis development and hepatocarcinogenesis, respectively.

RESULTS

DRI exerted a marked inhibitory effect against liver fibrosis development and glutathione-S-transferase placental form (GST-P) positive preneoplastic lesions along with suppression of the Ac-HSC and neovascularization in a dose-dependent manner. DRI also inhibited the hepatic expressions of transforming growth factor-beta 1 (TGF-beta 1), angiotensin-II (AT-II) and vascular endothelial growth factor (VEGF). These results indicated that renin played a pivotal role in the liver fibrosis development and hepatocarcinogenesis of NASH.

CONCLUSION

Because DRI is already widely used in the clinical practice with safety, this drug may represent a potential new strategy against the progression of NASH in the future.

Branched-chain amino acids ameliorate fibrosis and suppress tumor growth in a rat model of hepatocellular carcinoma with liver cirrhosis

Purpose

Recent studies have revealed that branched-chain amino acids (BCAA) reduce the development of hepatocellular carcinoma (HCC) in patients with obesity and hepatitis C virus infection by improving insulin resistance (IR). The aim of this study was to examine the anti-cancer and anti-fibrotic effects of BCAA on the development of diethylnitrosamine (DEN)-induced HCC and liver cirrhosis in a rat model.

Methods

Male SD rats received weekly intraperitoneal injections of DEN (50 mg/kg of body weight) for 16 weeks to induce HCC. They were fed a diet containing 3% casein, 3% or 6% BCAA for 13 weeks beginning 6 weeks after DEN administration. DEN was used to induce HCC through stepwise development from cirrhosis to HCC. The effect of BCAA was evaluated in tumor tissues by histopathologic analyses, reverse transcription-polymerase chain reaction, and Western blotting.

Results

The mean area and number of dysplastic nodules (DNs) and tumors in the casein group tended to be larger than those in the BCAA group 16 weeks after DEN administration. The mean fibrotic area in the BCAA group was smaller than that in the casein group. The BCAA group showed decreased mRNA levels for markers of fibrosis, angiogenesis, and apoptosis inhibition. Compared with the casein group, the BCAA group had lower levels of α-smooth muscle actin, vascular endothelial growth factor, p-β-catenin, p-p38 mitogen-activated protein kinase, proliferating cell nuclear antigen, and caspase-3 protein expression, as well as a higher level of cleaved caspase-3 protein expression.

Conclusions

BCAA supplementation of the diet ameliorated liver fibrosis and HCC development in a DEN-induced rat model of HCC with liver cirrhosis, but not in the IR model. These results provide a rationale for anti-fibrosis and chemoprevention using BCAA treatment for HCC with liver cirrhosis, as well as decreasing the ammonia level.

Long-term Branched Chain Amino Acid Supplementation Ameliorates Diethylnitrosamine-induced Liver Glutathione S-transferase-p Positivity in Zucker Fatty Rats

BACKGROUND

Obesity increases the risk of fatty liver disease and liver cancer. There are several models of obesity-associated hepatocellular carcinoma, but tumor development in these models is slow.

MATERIALS AND METHODS

We investigated Zucker fatty rats, a model of obesity and insulin resistance, to discover if diethylnitrosamine (DEN), a potent liver carcinogen, might enhance liver carcinogenesis. We also investigated the effect of branched chain amino acids (BCAA) against the development of liver cancer.

RESULTS

Incidence and number of hepatocellular carcinomas and adenomas were significantly greater in DEN-treated Zucker fatty rats than in DEN-treated lean rats. All treated Zucker fatty rats developed hepatocellular carcinoma within 16 weeks. Long-term BCAA supplementation significantly reduced expression of CyclinD1, PCNA, thymidine kinase, Bcl-2, and GST-p and increased expression of p21 in the liver. Furthermore, BCAA treatment significantly reduced the area of GST-p positive foci.

CONCLUSION

Long-term BCAA treatment may induces cell cycle arrest and apoptotic induction, thus suppressing pre-neoplastic lesions.

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.

Branched-chain amino acid supplementation reduces oxidative stress and prolongs survival in rats with advanced liver cirrhosis

Long-term supplementation with branched-chain amino acids (BCAA) is associated with prolonged survival and decreased frequency of development of hepatocellular carcinoma (HCC) in patients with liver cirrhosis. However, the pharmaceutical mechanism underlying this association is still unclear. We investigated whether continuous BCAA supplementation increases survival rate of rats exposed to a fibrogenic agent and influences the iron accumulation, oxidative stress, fibrosis, and gluconeogenesis in the liver. Further, the effects of BCAA on gluconeogenesis in cultured cells were also investigated. A significant improvement in cumulative survival was observed in BCAA-supplemented rats with advanced cirrhosis compared to untreated rats with cirrhosis (P<0.05). The prolonged survival due to BCAA supplementation was associated with reduction of iron contents, reactive oxygen species production and attenuated fibrosis in the liver. In addition, BCAA ameliorated glucose metabolism by forkhead box protein O1 pathway in the liver. BCAA prolongs survival in cirrhotic rats and this was likely the consequences of reduced iron accumulation, oxidative stress and fibrosis and improved glucose metabolism in the liver.

Branched-chain amino acids suppress the cumulative recurrence of hepatocellular carcinoma under conditions of insulin-resistance

Branched-chain amino acids (BCAAs) reportedly inhibit the incidence of hepatocellular carcinoma (HCC) in patients with liver cirrhosis and obesity that is frequently associated with insulin resistance (IR). We previously reported that BCAAs exert a chemopreventive effect against HCC under IR conditions in rats. The aim of the present study was to examine the effect of BCAAs on the cumulative recurrence of HCC under IR conditions in the clinical practice. BCAA granules (Livact^®, 12 g/day) were administered for 60 months following the local curative therapy for HCC, and several indices were determined. Treatment with BCAAs markedly inhibited the cumulative recurrence of HCC in patients with a high IR index [homeostasis model assessment (HOMA)-IR >2.5], but not in patients with HOMA-IR of ≤2.5. BCAA also improved the HOMA-IR, and the inhibitory effect was observed regardless of the serum albumin (Alb) levels. Similarly, BCAA treatment revealed a marked suppressive effect in patients with high fasting insulin [immune reactive insulin (IRI) >15 U/ml], but not with IRI of ≤15. BCAA treatment did not result in differences in HCC recurrence in patients with high and low glucose levels [fasting blood sugar (FBS) >110 and ≤110, respectively]. Furthermore, serum levels of the soluble form of vascular endothelial growth factor receptor 2 (sVEGFR2) were significantly inhibited along with these clinical effects. Our findings indicate that the inhibitory effect of BCAAs was achieved, at least partly, by coordinated effects of anti-angiogenesis and IR improvement. Since BCAAs are widely and safely used in clinical practice to treat patients with chronic liver diseases, BCAAs may represent a new strategy for secondary chemoprevention for HCC patients with IR. Moreover, our findings suggest that sVEGFR2 may be a useful clinical predictive marker for BCAA treatment under IR conditions.

The effect of long-term supplementation with branched-chain amino acid granules in patients with hepatitis C virus-related hepatocellular carcinoma after radiofrequency thermal ablation

GOALS

To elucidate whether long-term supplementation with branched-chain amino acid (BCAA) granules improves overall survival (OS) and recurrence-free survival (RFS) after radiofrequency thermal ablation (RFA) in patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC)≤3 cm in diameter with up to 3 nodules and a serum albumin level before RFA of ≤3.5 g/dL.

BACKGROUND

Whether BCAA treatment after curative RFA for patients with HCV-related HCC improves OS and RFS remains unclear.

STUDY

We compared the OS rate and the RFS rate between the BCAA group (n=115) and the control group (n=141). We also examined factors contributing to OS and RFS.

RESULTS

The 1 and 3 years OS rates after RFA were 94.0% and 70.0%, respectively, in the BCAA group, and 94.0% and 49.8%, respectively, in the control group (P=0.001). The corresponding RFS rates 1 and 3 years after RFA were 61.8% and 28.0%, respectively, in the BCAA group, and 52.0% and 12.0%, respectively, in the control group (P=0.013). In the multivariate analysis, in terms of OS, BCAA treatment, and serum albumin level of ≥3.4 g/dL, and in terms of RFS, age 70 years or older, BCAA treatment, and a serum albumin level of ≥3.4 g/dL were significant independent factors, respectively.

CONCLUSIONS

BCAA treatment may improve OS and RFS after RFA in patients with HCV-related HCC≤3 cm in diameter with up to 3 nodules and a serum albumin level before RFA of 3.5 g/dL.

Comparative studies of Acyl-CoA dehydrogenases for monomethyl branched chain substrates in amino acid metabolism

Short/branched chain acyl-CoA dehydrogenase (SBCAD), isovaleryl-CoA dehydrogenase (IVD), and isobutyryl-CoA dehydrogenase (IBD) are involved in metabolism of isoleucine, leucine, and valine, respectively. These three enzymes all belong to acyl-CoA dehydrogenase (ACD) family, and catalyze the dehydrogenation of monomethyl branched-chain fatty acid (mmBCFA) thioester derivatives. In the present work, the catalytic properties of rat SBCAD, IVD, and IBD, including their substrate specificity, isomerase activity, and enzyme inhibition, were comparatively studied. Our results indicated that SBCAD has its catalytic properties relatively similar to those of straight-chain acyl-CoA dehydrogenases in terms of their isomerase activity and enzyme inhibition, while IVD and IBD are different. IVD has relatively broader substrate specificity than those of the other two enzymes in accommodating various substrate analogs. The present study increased our understanding for the metabolism of monomethyl branched-chain fatty acids (mmBCFAs) and branched-chain amino acids (BCAAs), which should also be useful for selective control of a particular reaction through the design of specific inhibitors.

Nutritional status and quality of life in current patients with liver cirrhosis as assessed in 2007-2011

AIM

Current guidelines recommended adequate nutritional support for patients with liver cirrhosis to improve clinical outcome and quality of life (QOL). However, these evidences were obtained more than 10 years ago when malnutrition prevailed. In recent years, the impact of obesity on liver damage and carcinogenesis has grown. We attempted to elucidate the nutritional state and QOL in present cirrhotics.

METHODS

A research group supported by the Ministry of Health, Labor and Welfare of Japan recruited 294 cirrhotics between 2007 and 2011. Subjects comprised 171 males and 123 females, 158 of whom had hepatocellular carcinoma (HCC) and Child-Pugh grades A : B : C were 154:91:49. Anthropometry, blood biochemistry and indirect calorimetry were conducted, and QOL was measured using Short Form-8.

RESULTS

The mean body mass index (BMI) of all patients was 23.1 ± 3.4 kg/m(2) , and 31% showed obesity (BMI ≥ 25.0). In subjects without ascites, edema or HCC, mean BMI was 23.6 ± 3.6, and 34% had obesity. Protein malnutrition defined as serum albumin of less than 3.5 g/dL and energy malnutrition as respiratory quotient of less than 0.85 appeared in 61% and 43%, respectively, and protein-energy malnutrition (PEM) in 27% of all subjects. Among subjects without HCC, each proportion was 67%, 48% and 30%, respectively. QOL was significantly lower on all subscales than Japanese national standard values, but was similar regardless the presence or absence of HCC.

CONCLUSION

While PEM is still present in liver cirrhosis, an equal proportion has obesity in recent patients. Thus, in addition to guidelines for PEM, establishment of nutrition and exercise guidelines seems essential for obese patients with liver cirrhosis.

Preventive effects of branched-chain amino acid supplementation on the spontaneous development of hepatic preneoplastic lesions in C57BL/KsJ-db/db obese mice

Obesity and its associated disorders, such as non-alcoholic steatohepatitis, increase the risk of hepatocellular carcinoma. Branched-chain amino acids (BCAA), which improve protein malnutrition in patients with liver cirrhosis, reduce the risk of hepatocellular carcinoma in these patients with obesity. In the present study, the effects of BCAA supplementation on the spontaneous development of hepatic premalignant lesions, foci of cellular alteration, in db/db obese mice were examined. Male db/db mice were given a basal diet containing 3.0% of either BCAA or casein, a nitrogen-content-matched control of BCAA, for 36 weeks. On killing the mice, supplementation with BCAA significantly inhibited the development of foci of cellular alteration when compared with casein supplementation by inhibiting cell proliferation, but inducing apoptosis. BCAA supplementation increased the expression levels of peroxisome proliferator-activated receptor-γ, p21(CIP1) and p27(KIP1) messenger RNA and decreased the levels of c-fos and cyclin D1 mRNA in the liver. BCAA supplementation also reduced both the amount of hepatic triglyceride accumulation and the expression of interleukin (IL)-6, IL-1β, IL-18 and tumor necrosis factor-α mRNA in the liver. Increased macrophage infiltration was inhibited and the expression of IL-6, TNF-α, and monocyte chemoattractant protein-1 mRNA in the white adipose tissue were each decreased by BCAA supplementation. BCAA supplementation also reduced adipocyte size while increasing the expression of peroxisome proliferator-activated receptor-α, peroxisome proliferator-activated receptor-γ and adiponectin mRNA in the white adipose tissue compared with casein supplementation. These findings indicate that BCAA supplementation inhibits the early phase of obesity-related liver tumorigenesis by attenuating chronic inflammation in both the liver and white adipose tissue. BCAA supplementation may be useful in the chemoprevention of liver tumorigenesis in obese individuals.

Obesity and hepatocellular carcinoma: targeting obesity-related inflammation for chemoprevention of liver carcinogenesis

Obesity and related metabolic abnormalities, including a state of chronic inflammation, increase the risk of hepatocellular carcinoma (HCC). Adipose tissue constitutively expresses the proinflammatory cytokine tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), which are important tumor promoters in inflammation-related carcinogenesis. Dysregulation of TNF-α and IL-6 is associated with the development of steatosis and inflammation within the liver. These cytokines also lie at the core of the association between obesity and insulin resistance, which is a key factor in the development of obesity-related HCC. Here we present a detailed review of the relationship between metabolic abnormalities and the development of HCC, focusing on the role played by inflammation. Drawing from our basic and clinical research, the present report also reviews evidence that targeting metabolic abnormalities, such as attenuation of chronic inflammation and improvement of insulin resistance by either pharmaceutical or nutritional intervention, may be an effective strategy in preventing the development of HCC in obese individuals.

Oral supplementation of branched-chain amino acids reduces early recurrence after hepatic resection in patients with hepatocellular carcinoma: a prospective study

PURPOSES

The long-term outcomes of branched-chain amino acids (BCAA) administration after hepatic resection in patients with hepatocellular carcinoma (HCC) remain unclear. This study assessed the effect of oral supplementation with BCAA on the development of liver tumorigenesis after hepatic resection in HCC patients.

METHODS

Fifty-six patients were randomly assigned to receive either BCAA supplementation (Livact group, n = 26) or a conventional diet (Control group, n = 30). Twenty-six patients in the BCAA group were treated orally for 2 weeks before and 6 months after hepatic resection. Postoperative tumor recurrence was continuously evaluated in all patients by measuring various clinical parameters.

RESULTS

There was no significant difference in the overall survival rate between the two patient groups; however, the recurrence rate at 30 months after surgery was significantly better in the Livact group in comparison to the Control group. Interestingly, the tumor markers, such as AFP and PIVKA-II, significantly decreased at 36 months after liver resection in the Livact group in comparison to the Control group.

CONCLUSIONS

Oral supplementation of BCAA reduces early recurrence after hepatic resection in patients with HCC. This treatment regimen offers potential benefits for clinical use in such patients, even in cases with a well-preserved preoperative liver function.

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.

Nutraceutical approach for preventing obesity-related colorectal and liver carcinogenesis

Obesity and its related metabolic abnormalities, including insulin resistance, alterations in the insulin-like growth factor-1 (IGF-1)/IGF-1 receptor (IGF-1R) axis, and the state of chronic inflammation, increase the risk of colorectal cancer (CRC) and hepatocellular carcinoma (HCC). However, these findings also indicate that the metabolic disorders caused by obesity might be effective targets to prevent the development of CRC and HCC in obese individuals. Green tea catechins (GTCs) possess anticancer and chemopreventive properties against cancer in various organs, including the colorectum and liver. GTCs have also been known to exert anti-obesity, antidiabetic, and anti-inflammatory effects, indicating that GTCs might be useful for the prevention of obesity-associated colorectal and liver carcinogenesis. Further, branched-chain amino acids (BCAA), which improve protein malnutrition and prevent progressive hepatic failure in patients with chronic liver diseases, might be also effective for the suppression of obesity-related carcinogenesis because oral supplementation with BCAA reduces the risk of HCC in obese cirrhotic patients. BCAA shows these beneficial effects because they can improve insulin resistance. Here, we review the detailed relationship between metabolic abnormalities and the development of CRC and HCC. We also review evidence, especially that based on our basic and clinical research using GTCs and BCAA, which indicates that targeting metabolic abnormalities by either pharmaceutical or nutritional intervention may be an effective strategy to prevent the development of CRC and HCC in obese individuals.

Protective effects of fermented rice vinegar sediment (Kurozu moromimatsu) in a diethylnitrosamine-induced hepatocellular carcinoma animal model

Kurozu moromimatsu is the sediment of Kurozu, a jar-fermented Japanese black vinegar produced from unpolished rice. Here, we examined the protective effects of Kurozu moromimatsu in a diethylnitrosamine-induced model of hepatocellular carcinoma. Thirty-two F344 rats were divided into two groups; the control group received basal CE-2 diet, and the Kurozu moromimatsu group received CE-2 diet containing Kurozu moromimatsu. At 16 weeks after initial intraperitoneal administration of diethylnitrosamine (150 mg/kg/week), serum was collected from half the rats. These rats were sacrificed and the liver was resected for histological examination of hematoxylin-eosin-stained sections and assay of matrix metalloproteinase-2 and matrix metalloproteinase-9 levels in tumor tissues. Glutathione S-transferase placental form-positive foci were evaluated by immunostaining for glutathione S-transferase placental form. The remaining rats were maintained for evaluation of survival. There were no significant differences of serum transaminases, tumor necrosis factor-alpha, and also no marked hepatic histological differences, between the two groups. However, the size of hepatocellular carcinomas was greatly decreased and the levels of activated matrix metalloproteinase-2 and -9 were significantly reduced in the Kurozu moromimatsu group. Further, survival was significantly prolonged in the Kurozu moromimatsu group compared with the control. These results indicate that Kurozu moromimatsu inhibited the growth of hepatocellular carcinoma.

Evaluation of gastrointestinal injury and blood flow of small bowel during low-dose aspirin administration

Low-dose acetylsalicylic acid has been widely used. We evaluated small bowel and gastric injuries during acetylsalicylic acid administration using video capsule endoscopy and gastroduodenal endoscopy. We also investigated blood flow using contrast-enhanced ultrasonography. Six healthy volunteers were enrolled in this preliminary study. The subjects were administered 100 mg of enteric-coated aspirin daily for 14 days. Video capsule endoscopy and gastroduodenal endoscopy were simultaneously performed before administration and on days 1, 3, 7 and 14. Contrast-enhanced ultrasonography was performed before administration and on day 2, and 8. Video capsule endoscopy after administration of low-dose acetylsalicylic acid revealed small bowel mucosal damages of petechiae and erythema in all cases, and denuded area in one case. The total number of lesions in the small bowel increased according to duration of low-dose acetylsalicylic acid administration. However, the total number of lesions in the stomach peaked on day 3. Contrast-enhanced ultrasonography showed that the time-intensity curve peak value and Areas under the curves after acetylsalicylic acid administration were reduced. We observed not only gastric mucosal injuries but also small intestinal injuries with short-term low-dose acetylsalicylic acid administration. Acetylsalicylic acid administration also caused a decrease in small intestinal blood flow. Contrast-enhanced ultrasonography is useful for evaluation blood flow in the small bowel mucosa.

Attenuation of insulin-resistance-based hepatocarcinogenesis and angiogenesis by combined treatment with branched-chain amino acids and angiotensin-converting enzyme inhibitor in obese diabetic rats

BACKGROUND

Insulin resistance (IR) is reportedly involved in the progression of hepatocellular carcinoma (HCC). Because neovascularization plays an important role in HCC, including hepatocarcinogenesis, an angiostatic therapy would be a promising approach for chemoprevention against HCC. The aim of the present study was to examine the combined effect of clinically used branched-chain amino acids (BCAAs) and an angiotensin-converting enzyme inhibitor (ACE-I), in conjunction with neovascularization, on hepatocarcinogenesis under the condition of IR.

METHODS

The combined effect of the treatment on the development of liver enzyme-altered preneoplastic lesions, angiogenesis, and several indices was elucidated in obese diabetic rats. We also performed several sets of in vitro experiments to examine the mechanisms involved.

RESULTS

When used individually, both BCAAs and ACE-I at clinically comparable low doses significantly attenuated the development of preneoplastic lesions, along with the suppression of both angiogenesis and vascular endothelial growth factor (VEGF) expression. The combination treatment with both agents exerted a more potent inhibitory effect than that of either single agent. Our in vitro study showed a similar combined effect on endothelial cell tubule formation.

CONCLUSION

This combination regimen showed a marked chemopreventive effect against hepatocarcinogenesis, along with suppression of neovascularization and VEGF expression, in obese diabetic rats. Because both BCAAs and ACE-Is are widely used in clinical practice, this combination therapy may represent a potential new strategy for chemoprevention against IR-based HCC in the future.

Insulin resistance raises the risk for recurrence of stage I hepatocellular carcinoma after curative radiofrequency ablation in hepatitis C virus-positive patients: A prospective, case series study

AIM

Several studies have reported that insulin resistance raises the risk of primary hepatocellular carcinoma (HCC). We conducted a prospective, case series study to test the impact of insulin resistance on the recurrence after curative radiofrequency ablation (RFA) of stage I HCC in HCV-positive patients.

METHODS

From January 2006 to December 2007, 226 consecutive patients underwent treatment for primary HCC at our institutions, including 37 stage I cases. Among them, 33 were HCV-positive, and three, six and 24 received curative surgery, transarterial chemoembolization or RFA, respectively. In the 24 patients treated with RFA, recurrence-free survival was analyzed using the Kaplan-Meier method. The factors contributing to recurrence of HCC were subjected to univariate and multivariate analyses using the Cox proportional hazards model. Insulin resistance was estimated by the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR).

RESULTS

Kaplan-Meier analysis showed that the recurrence-free survival was lower in patients with higher HOMA-IR (>2.3, P = 0.0252) or with lower serum albumin level (<3.3 g/dL, P = 0.0004). In the univariate analysis, HOMA-IR (P = 0.0420) and albumin (P = 0.0036) were significantly associated with recurrence of HCC. Multivariate analysis revealed albumin (odds ratio = 0.01, 95% confidence interval = 0.0002-0.015, P = 0.0001) and HOMA-IR (odds ratio = 3.85, 95% confidence interval = 1.57-14.2, P = 0.0015) to be independent predictors for recurrence of HCC.

CONCLUSION

Serum albumin level and HOMA-IR were independent risk factors for recurrence of stage I HCC after curative RFA in HCV-positive patients. Patients with these factors require closer surveillance.

Dietary supplementation with branched-chain amino acids suppresses diethylnitrosamine-induced liver tumorigenesis in obese and diabetic C57BL/KsJ-db/db mice

Obesity and related metabolic abnormalities, including insulin resistance, are risk factors for hepatocellular carcinoma in non-alcoholic steatohepatitis as well as in chronic viral hepatitis. Branched-chain amino acids (BCAA), which improve insulin resistance, inhibited obesity-related colon carcinogenesis in a rodent model, and also reduced the incidence of hepatocellular carcinoma in obese patients with liver cirrhosis. In the present study, we determined the effects of BCAA on the development of diethylnitrosamine (DEN)-induced liver tumorigenesis in obese C57BL/KsJ-db/db (db/db) mice with diabetes mellitus. Male db/db mice were given tap water containing 40 ppm DEN for an initial 2 weeks and thereafter they received a basal diet containing 3.0% of BCAA or casein, which served as a nitrogen content-matched control of BCAA, throughout the experiment. Supplementation with BCAA significantly reduced the total number of foci of cellular alteration, a premalignant lesion of the liver, and the expression of insulin-like growth factor (IGF)-1, IGF-2, and IGF-1 receptor in the liver when compared to the casein supplementation. BCAA supplementation for 34 weeks also significantly inhibited both the development of hepatocellular neoplasms and the proliferation of hepatocytes in comparison to the basal diet or casein-fed groups. Supplementation with BCAA improved liver steatosis and fibrosis and inhibited the expression of alpha-smooth muscle actin in the DEN-treated db/db mice. The serum levels of glucose and leptin decreased by dietary BCAA, whereas the value of the quantitative insulin sensitivity check index increased by this agent, indicating the improvement of insulin resistance and hyperleptinemia. In conclusion, oral BCAA supplementation improves insulin resistance and prevents the development of liver tumorigenesis in obese and diabetic mice.

Molecular signatures of noncancerous liver tissue can predict the risk for late recurrence of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive malignancy mainly due to tumor metastases or recurrence even after undergoing potentially curative treatment. There are two types of HCC recurrence. The early and late tumor recurrences appear in distinct biological contexts, and their clinical courses are quite different. Therefore, it is important to precisely and distinctly discriminate the risk of each type of HCC recurrence. Many researchers have used DNA microarray technology to reclassify HCC with respect to its malignant potential. Some of these studies successfully identified specific gene-expression signatures derived from the cancerous tissues of HCC for predicting the early recurrence due to intrahepatic metastasis. However, there are no well-defined predictors for late recurrence. Recently, a few studies have focused on the nontumorous portion of liver tissues to predict late recurrence, possibly due to de novo hepatocarcinogenesis based on the idea of "field cancerization." This study reviewed the possible value of a gene-expression analysis of noncancerous liver tissue to clarify the risk for multicentric late recurrence of HCC. These findings may have important implications for chemopreventive strategies and tailored surveillance programs. Furthermore, this approach may also be applicable to other multifocal tumors, such as head and neck carcinoma.

Crosstalk between angiogenesis, cytokeratin-18, and insulin resistance in the progression of non-alcoholic steatohepatitis

AIM: To elucidate the possible crosstalk between angiogenesis, cytokeratin-18 (CK-18), and insulin resistance (IR) especially in patients with non-alcoholic steatohepatitis (NASH).

METHODS: Twenty-eight patients with NASH and 11 with simple fatty liver disease (FL) were enrolled in this study and underwent clinicopathological examination. The measures of angiogenesis, CK-18, and IR employed were CD34-immunopositive vessels, CK-18-immunopositive cells, and homeostasis model assessment of IR (HOMA-IR), respectively. The correlations of these factors with NASH were elucidated.

RESULTS: Significant development of hepatic neovascularization was observed only in NASH, whereas almost no neovascularization could be observed in FL and healthy liver. The degree of angiogenesis was almost parallel to liver fibrosis development, and both parameters were positively correlated. Similarly, CK-18 expression and HOMA-R were significantly increased in NASH as compared with FL and healthy liver. Furthermore, CK-18 and HOMA-IR were also positively correlated with the degree of neovascularization.

CONCLUSION: These results indicate that the crosstalk between angiogenesis, CK-18, and IR may play an important role in the onset and progression of NASH.