Junpei Iwasa

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 α‐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. (Cancer Sci 2009)

Supplementation with Branched-chain Amino Acids Inhibits Azoxymethane-induced Colonic Preneoplastic Lesions in Male C57BL/KsJ-db/db Mice

Purpose: Obesity and related metabolic abnormalities, including insulin resistance and activation of the insulin-like growth factor (IGF)/IGF-I receptor (IGF-IR) axis, are risk factors for colon cancer. Supplementation with branched-chain amino acids (BCAA) reduces the risk of liver cancer in cirrhotic patients who are obese, and this has been associated with an improvement of insulin resistance. The present study examined the effects of BCAA on the development of azoxymethane (AOM)-initiated colonic premalignant lesions in C57BL/KsJ-db/db (db/db) mice that were obese and had hyperinsulinemia. Experimental Design: Male db/db mice were given 4 weekly s.c. injections of AOM (15 mg/kg of body weight) and then they were fed a diet containing 3.0% BCAA or casein, a nitrogenc content–matched control diet, for 7 weeks. Results: Feeding with BCAA caused a significant reduction in the number of total aberrant crypt foci and β-catenin accumulated crypts, both of which are premalignant lesions of the colon, compared with the control diet–fed groups. BCAA supplementation caused a marked decrease in the expression of IGF-IR, the phosphorylated form of IGF-IR, phosphorylated glycogen synthase kinase 3β, phosphorylated Akt, and cyclooxygenase-2 proteins on the colonic mucosa of AOM-treated mice. The serum levels of insulin, IGF-I, IGF-II, triglyceride, total cholesterol, and leptin were also decreased by supplementation with BCAA. Conclusion: BCAA supplementation in diet improves insulin resistance and inhibits the activation of the IGF/IGF-IR axis, thereby preventing the development of colonic premalignancies in an obesity-related colon cancer model that was also associated with hyperlipidemia and hyperinsulinemia. BCAA, therefore, may be a useful chemoprevention modality for colon cancer in obese people.

(-)-Epigallocatechin gallate prevents carbon tetrachloride-induced rat hepatic fibrosis by inhibiting the expression of the PDGFRβ and IGF-1R.

Hepatic fibrosis is a major complication of various chronic liver diseases. Activated hepatic stellate cells (HSCs) play a critical role in the development of liver fibrosis and the axis of platelet-derived growth factor (PDGF)/PDGF receptor (PDGFR), a member of receptor tyrosine kinases (RTKs), is closely associated with the activation of HSC. Insulin-like growth factor (IGF)-1 receptor (IGF-1R), which also belongs to RTKs, interacts with the PDGF/PDGFR axis, thereby cooperatively promoting hepatic fibrosis. We herein examined the effects of (-)-epigallocatechin gallate (EGCG), which inhibits the activation of several types of RTKs, on the development of rat liver fibrosis induced by carbon tetrachloride (CCl4). Drinking water with 0.1% EGCG significantly decreased the serum levels of both aspartate aminotransferase and alanine aminotransferase raised by CCl4, thus indicating an improvement of liver injury. In CCl4-injected rats, EGCG markedly attenuated hepatic fibrosis and decreased the amount of hydroxyproline in the experimental liver. The expression of PDGFRbeta and IGF-1R mRNAs in the liver was significantly lowered by the treatment with EGCG. EGCG also decreased the expression of PDGFRbeta and alpha-smooth muscle actin proteins, thus indicating the inhibition of HSC activation. These findings suggest that EGCG can exert, at least in part, an anti-fibrotic effect on the liver by targeting PDGFRbeta and IGF-1R. EGCG might therefore be useful in both the prevention and treatment of hepatic fibrosis.

Acyclic Retinoid Inhibits Diethylnitrosamine-Induced Liver Tumorigenesis in Obese and Diabetic C57BLKS/J- +Leprdb/+Leprdb Mice

Obesity and the related metabolic abnormalities are associated with increased risk of hepatocellular carcinoma (HCC). Malfunctioning of retinoid X receptor (RXR) α due to phosphorylation by Ras/MAPK also plays a critical role in liver carcinogenesis. In the present study, we examined the effects of acyclic retinoid (ACR), which targets RXRα, on the development of diethylnitrosamine (DEN)-induced liver tumorigenesis in C57BLKS/J- +Leprdb/+Leprdb (db/db) obese mice. Male db/db mice were given tap water containing 40 ppm DEN for 2 weeks, after which they were fed a diet containing 0.03% or 0.06% of ACR throughout the experiment. In mice treated with either dose of ACR for 34 weeks, the development of liver cell adenomas was significantly inhibited as compared with basal diet-fed mice. ACR markedly inhibited the activation of Ras and phosphorylation of the ERK (extracellular signal-regulated kinase) and RXRα proteins in the livers of experimental mice. It also increased the expression of RAR β and p21CIP1 mRNA while decreasing the expression of cyclin D1, c-Fos, and c-Jun mRNA in the liver, thereby restoring RXRα function. Administration of ACR improved liver steatosis and activated the AMPK protein. The serum levels of insulin decreased by ACR treatment, whereas the quantitative insulin sensitivity check index (QUICKI) values increased, indicating improved insulin sensitivity. The serum levels of TNF-α and the expression levels of TNF- α, IL-6, and IL-1 β mRNA in the livers of DEN-treated db/db mice were decreased by ACR treatment, suggesting attenuation of the chronic inflammation induced by excessive fatty deposits. ACR may be, therefore, useful in the chemoprevention of obesity-related HCC. Cancer Prev Res; 4(1); 128–36. ©2010 AACR.

Long-term outcome of branched-chain amino acid treatment in patients with liver cirrhosis

Clinical impact of protein‐energy malnutrition (PEM) on the outcome of liver cirrhosis is well documented. As a candidate interventional modality to improve PEM in cirrhosis, effects of branched‐chain amino acid (BCAA) supplementation on event‐free survival and quality of life (QOL) was first reported by Yoshida et al. in 1989. Although critical arguments still continue regarding the effects of BCAA, several randomized trials in the last 5 years have brought positive results, and seem to have settled the discussion in a favorable direction for the efficacy of BCAA in liver cirrhosis. Actually, The European Society for Clinical Nutrition and Metabolism (ESPEN) upgraded the recommendation of BCAA supplementation in decompensated liver cirrhosis in the latest revision of its guidelines in 2006, by referring to the literatures from Italy and Japan. Particularly in these two long‐term randomized studies with 1–2 years‐supplementation, event‐free survival was estimated by employing composite endpoints such as aggravation of hepatic failure (ascites, peripheral edema, hepatic encephalopathy, and jaundice), rupture of esophageal or gastric varices, development of liver cancer, and death from any cause. Both trials agreed on the effect of BCAA to reduce the incidence of hepatic failure, thus contributing to the rise in the event‐free survival. Quality of life is another essential marker of outcome survey. Marchesini, Muto, and Nakaya reported the improved QOL in cirrhotics with BCAA supplementation. In particular, quantitative analysis of QOL measured by Short Form 36 (SF‐36) questionnaire demonstrated a significant recovery of general heath perception score in BCAA supplemented patients in a randomized trial. In this article, the long‐term outcome of BCAA treatment in liver cirrhosis will be reviewed with its action mechanisms. In addition, the effects of BCAA treatment on the incidence of liver cancer in obese patients with type C liver cirrhosis, significance of obesity as a risk factor for type C liver cancer, and a possible role of Body Mass Index to estimate the histological grade of fat deposition in the liver will be briefly discussed.

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.

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

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

Elevated serum tumor necrosis factor-α and soluble tumor necrosis factor receptors correlate with aberrant energy metabolism in liver cirrhosis

OBJECTIVE Protein-energy malnutrition is frequently observed in patients with liver cirrhosis and is associated with their poor prognosis. Tumor necrosis factor-alpha (TNF-alpha) is elevated in those patients and may contribute to the alterations of energy metabolism. Our aim was to characterize the aberrant energy metabolism in cirrhotic patients with regard to TNF-alpha. METHODS Twenty-four patients (mean age 65 +/- 6 y) with viral liver cirrhosis who did not have hepatocellular carcinoma or acute infections were studied. Twelve healthy volunteers were recruited after matching for age, gender, and body mass index with the patients and served as controls (59 +/- 8 y). Serum levels of TNF-alpha, soluble 55-kDa TNF receptor (sTNF-R55), soluble 75-kDa TNF receptor (sTNF-R75), and leptin were determined by immunoassay. Substrate oxidation rates of carbohydrate and fat were estimated by indirect calorimetry after overnight bedrest and fasting. RESULTS In cirrhotic patients, serum levels of TNF-alpha, sTNF-R55, and sTNF-R75 were significantly higher than those in the controls and correlated with the increasing grade of disease severity as defined by Child-Pugh classification. Serum leptin concentration was not different between cirrhotics and controls but correlated with their body mass index. The decrease in substrate oxidation rate of carbohydrate and the increase in substrate oxidation rate of fat significantly correlated with serum TNF-alpha, sTNF-R55, and sTNF-R75 concentrations. CONCLUSION Tumor necrosis factor-alpha might be associated with the aberrant energy metabolism in patients with liver cirrhosis.

First Report of Acute Cholecystitis with Sepsis Caused by Cellulomonas denverensis

ABSTRACT Cellulomonas denverensis is a small and thin gram-positive rod-shaped bacterium that was proposed as a new species in 2005. Here we report a female case of acute cholecystitis and sepsis in which C. denverensis was determined to be causative.

Endoscopic treatment for benign biliary strictures: Can placement of a covered metallic stent be an option in refractory cases?

Background:  Recently, endoscopic treatment has been attempted to counter benign biliary strictures. It is expected to be an alternative to surgical operation because of its lower morbidity and its convenience, but the long‐term results have not yet been sufficiently elucidated. Here, we evaluate the short‐ and long‐term results of endoscopic stenting in patients with benign biliary strictures, and also describe a new technique using a covered metallic stent (CMS) in the refractory cases.