BackgroundOptimal treatment for nonalcoholic steatohepatitis (NASH) has not yet been established, particularly for individuals without diabetes. We examined the effects of metformin, commonly used to treat patients with type 2 diabetes, on liver pathology in a non-diabetic NASH mouse model.Methodology/Principal FindingsEight-week-old C57BL/6 mice were fed a methionine- and choline-deficient plus high fat (MCD+HF) diet with or without 0.1% metformin for 8 weeks. Co-administration of metformin significantly decreased fasting plasma glucose levels, but did not affect glucose tolerance or peripheral insulin sensitivity. Metformin ameliorated MCD+HF diet-induced hepatic steatosis, inflammation, and fibrosis. Furthermore, metformin significantly reversed hepatic steatosis and inflammation when administered after the development of experimental NASH.Conclusions/SignificanceThese histological changes were accompanied by reduced hepatic triglyceride content, suppressed hepatic stellate cell activation, and the downregulation of genes involved in fatty acid metabolism, inflammation, and fibrogenesis. Metformin prevented and reversed steatosis and inflammation of NASH in an experimental non-diabetic model without affecting peripheral insulin resistance.

Aims/hypothesis The cholesterol absorption inhibitor ezetimibe has been shown to ameliorate non-alcoholic fatty liver disease (NAFLD) pathology in a single-armed clinical study and in experimental animal models. In this study, we investigated the efficacy of ezetimibe on NAFLD pathology in an open-label randomised controlled clinical trial. Methods We had planned to enrol 80 patients in the trial, as we had estimated that, with this sample size, the study would have 90% power. The study intervention and enrolment were discontinued because of the higher proportion of adverse events (significant elevation in HbA 1c ) in the ezetimibe group than in the control group. Thirty-two patients with NAFLD were enrolled and randomised (allocation by computer program). Ezetimibe (10 mg/day) was given to 17 patients with NAFLD for 6 months. The primary endpoint was change in serum aminotransferase level. Secondary outcomes were change in liver histology (12 control and 16 ezetimibe patients), insulin sensitivity including a hyperinsulinaemic-euglycaemic clamp study (ten control and 13 ezetimibe patients) and hepatic fatty acid composition (six control and nine ezetimibe patients). Hepatic gene expression profiling was completed in 15 patients using an Affymetrix gene chip. Patients and the physician in charge knew to which group the patient had been allocated, but people carrying out measurements or examinations were blinded to group. Results Serum total cholesterol was significantly decreased in the ezetimibe group. The fibrosis stage and ballooning score were also significantly improved with ezetimibe treatment. However, ezetimibe treatment significantly increased HbA 1c and was associated with a significant increase in hepatic longchain fatty acids. Hepatic gene expression analysis showed coordinate downregulation of genes involved in skeletal muscle development and cell adhesion molecules in the ezetimibe treatment group, suggesting a suppression of stellate cell development into myofibroblasts. Genes involved in the L-carnitine pathway were coordinately downregulated by ezetimibe treatment and those in the steroid metabolism pathway upregulated, suggestive of impaired oxidation of long-chain fatty acids. Conclusions/interpretation Ezetimibe improved hepatic fibrosis but increased hepatic long-chain fatty acids and HbA 1c in patients with NAFLD. These findings shed light on previously unrecognised actions of ezetimibe that should be examined further in future studies.

Background/Purpose Intra-abdominal arterial hemorrhage is still one of the most serious complications after pancreato-biliary surgery. We retrospectively analyzed our experiences with 15 patients in order to establish a therapeutic strategy for postoperative arterial hemorrhage following pancreato-biliary surgery.

Chronic endoplasmic reticulum (ER) stress is a major contributor to obesity-induced insulin resistance in the liver. However, the molecular link between obesity and ER stress remains to be identified. Proteasomes are important multicatalytic enzyme complexes that degrade misfolded and oxidized proteins. Here, we report that both mouse models of obesity and diabetes and proteasome activator (PA)28-null mice showed 30–40% reduction in proteasome activity and accumulation of polyubiquitinated proteins in the liver. PA28-null mice also showed hepatic steatosis, decreased hepatic insulin signaling, and increased hepatic glucose production. The link between proteasome dysfunction and hepatic insulin resistance involves ER stress leading to hyperactivation of c-Jun NH2-terminal kinase in the liver. Administration of a chemical chaperone, phenylbutyric acid (PBA), partially rescued the phenotypes of PA28-null mice. To confirm part of the results obtained from in vivo experiments, we pretreated rat hepatoma-derived H4IIEC3 cells with bortezomib, a selective inhibitor of the 26S proteasome. Bortezomib causes ER stress and insulin resistance in vitro—responses that are partly blocked by PBA. Taken together, our data suggest that proteasome dysfunction mediates obesity-induced ER stress, leading to insulin resistance in the liver.