Exercise retards hepatocarcinogenesis in obese mice independently of weight control.

Background & Aims: Obesity and type 2 diabetes increase hepatocellular carcinoma (HCC) incidence in humans and accelerate diethylnitrosamine (DEN)-induced hepatocarcinogenesis in mice. We investigated whether exercise reduces HCC development in obese/diabetic Alms1 mutant (foz/foz) mice and studied protective mechanisms.

Methods: We measured HCC development in DEN-injected male foz/foz and wild-type (WT) littermates housed with or without an exercise wheel from week 4 until 12 or 24 weeks, and in foz/foz mice pair-fed to WT littermates.

Cholesterol Crystals in Hepatocyte Lipid Droplets Are Strongly Associated With Human Nonalcoholic Steatohepatitis.

It is unclear what drives the development of fibrosing nonalcoholic steatohepatitis (NASH). We aimed to determine whether cholesterol crystallization within hepatocyte lipid droplets (LDs) distinguishes patients with fibrosing NASH from patients with isolated hepatic steatosis and to study pathways leading to cholesterol accumulation in hepatocyte LDs Patients with fibrosing NASH (n = 16) were compared to patients with isolated steatosis (n = 14). Almost all patients with fibrosing NASH had free cholesterol staining by filipin (16/16) and cholesterol crystals (15/16) in hepatocyte LDs, mostly in association with the LD membrane, compared to only 3/14 with cholesterol crystals and 3/14 with faint filipin staining in patients with isolated steatosis ( < 0.

Dietary cholesterol promotes steatohepatitis related hepatocellular carcinoma through dysregulated metabolism and calcium signaling.

The underlining mechanisms of dietary cholesterol and nonalcoholic steatohepatitis (NASH) in contributing to hepatocellular carcinoma (HCC) remain undefined. Here we demonstrated that high-fat-non-cholesterol-fed mice developed simple steatosis, whilst high-fat-high-cholesterol-fed mice developed NASH. Moreover, dietary cholesterol induced larger and more numerous NASH-HCCs than non-cholesterol-induced steatosis-HCCs in diethylnitrosamine-treated mice.

TLR9 is up-regulated in human and murine NASH: pivotal role in inflammatory recruitment and cell survival.

Unlabelled: Background and aims TLR9 deletion protects against steatohepatitis due to choline-amino acid depletion and high-fat diet. We measured in human non-alcoholic steatohepatitis (NASH) livers, and tested whether TLR9 mediates inflammatory recruitment in three murine models of non-alcoholic fatty liver disease (NAFLD). Methods We assayed TLR mRNA in liver biopsies from bariatric surgery patients.

Cholesterol crystallization within hepatocyte lipid droplets and its role in murine NASH.

We recently reported that cholesterol crystals form in hepatocyte lipid droplets (LDs) in human and experimental nonalcoholic steatohepatitis. Herein, we assigned WT C57BL/6J mice to a high-fat (15%) diet for 6 months, supplemented with 0%, 0.25%, 0.

Obeticholic acid improves adipose morphometry and inflammation and reduces steatosis in dietary but not metabolic obesity in mice.

Objective: Nonalcoholic steatohepatitis (NASH) is the outcome of interactions between overnutrition, energy metabolism, and adipose function. Obeticholic acid (OCA) improves steatosis in patients but for unknown reasons does not resolve NASH pathology. This study therefore investigated OCA effects in Wt mice, which develop obesity with atherogenic dietary feeding, and appetite-dysregulated, Alms1 mutant foz/foz mice fed the same diet, which develop metabolic obesity and diabetes.

Obesity and diabetes accelerate hepatocarcinogenesis via hepatocyte proliferation independent of NF-κB or Akt/mTORC1.

Background: There are strong links between obesity, diabetes and hepatocellular carcinoma (HCC), but molecular mechanisms remain unclear.

Aim: We tested the proposed involvement of NF-κB, IL-6/STAT3 and Akt/mTORC1 before onset (at 3 months) and at onset (6 months) of accelerated hepatocarcinogenesis in DEN-injected obese and diabetic compared to lean wildtype () mice, and also studied the hepatocyte proliferative response to DNA damage between the obese and lean lines.

Methods: Male and littermates fed normal chow were DEN-injected (10mg/kg i.

Cholesterol-lowering drugs cause dissolution of cholesterol crystals and disperse Kupffer cell crown-like structures during resolution of NASH.

Cholesterol crystals form within hepatocyte lipid droplets in human and experimental nonalcoholic steatohepatitis (NASH) and are the focus of crown-like structures (CLSs) of activated Kupffer cells (KCs). Obese, diabetic Alms1 mutant (foz/foz) mice were a fed high-fat (23%) diet containing 0.2% cholesterol for 16 weeks and then assigned to four intervention groups for 8 weeks: a) vehicle control, b) ezetimibe (5 mg/kg/day), c) atorvastatin (20 mg/kg/day), or d) ezetimibe and atorvastatin.

Anti-apoptotic phenotypes of cholestan-3β,5α,6β-triol-resistant human cholangiocytes: characteristics contributing to the genesis of cholangiocarcinoma.

The oxysterols cholestan-3β,5α,6β-triol (Triol) and 3-keto-cholest-4-ene (3K4) are increased in Opisthorchis viverrini-associated hamster cholangiocarcinoma and induce DNA damage and apoptosis via a mitochondria-dependent mechanism in MMNK-1 human cholangiocytes. Based on these observations, we hypothesized that chronic exposure of cholangiocytes to these pathogenic oxysterols may allow a growth advantage to a subset of these cells through selection for resistance to apoptosis, thereby contributing to cholangiocarcinogenesis. To test this hypothesis, we cultured MMNK-1 cells long-term in the presence of Triol.

Dietary modification dampens liver inflammation and fibrosis in obesity-related fatty liver disease.

Background: Alms1 mutant (foz/foz) mice develop hyperphagic obesity, diabetes, metabolic syndrome, and fatty liver (steatosis). High-fat (HF) feeding converts pathology from bland steatosis to nonalcoholic steatohepatitis (NASH) with fibrosis, which leads to cirrhosis in humans.

Objective: We sought to establish how dietary composition contributes to NASH pathogenesis.

Pharmacological cholesterol lowering reverses fibrotic NASH in obese, diabetic mice with metabolic syndrome.

Background & Aims: We have recently showed that hyperinsulinemia promotes hepatic free cholesterol (FC) accumulation in obese, insulin-resistant Alms1 mutant (foz/foz) mice with NASH. Here we tested whether cholesterol-lowering drugs reduce stress-activated c-Jun N-terminal kinase (JNK) activation, hepatocyte injury/apoptosis, inflammation, and fibrosis in this metabolic syndrome NASH model.

Methods: Female foz/foz and WT mice were fed HF (0.

Hepatic cholesterol crystals and crown-like structures distinguish NASH from simple steatosis.

We sought to determine whether hepatic cholesterol crystals are present in patients or mice with nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NASH), and whether their presence or distribution correlates with the presence of NASH as compared with simple steatosis. We identified, by filipin staining, free cholesterol within hepatocyte lipid droplets in patients with NASH and in C57BL/6J mice that developed NASH following a high-fat high-cholesterol diet. Under polarized light these lipid droplets exhibited strong birefringence suggesting that some of the cholesterol was present in the form of crystals.

Synergistic interaction of dietary cholesterol and dietary fat in inducing experimental steatohepatitis.

Unlabelled: The majority of patients with nonalcoholic fatty liver disease (NAFLD) have "simple steatosis," which is defined by hepatic steatosis in the absence of substantial inflammation or fibrosis and is considered to be benign. However, 10%-30% of patients with NAFLD progress to fibrosing nonalcoholic steatohepatitis (NASH), which is characterized by varying degrees of hepatic inflammation and fibrosis, in addition to hepatic steatosis, and can lead to cirrhosis. The cause(s) of progression to fibrosing steatohepatitis are unclear.

Identification of biliary bile acids in patients with benign biliary diseases, hepatocellular carcinoma and cholangiocarcinoma.

Bile acids are implicated as aetiological factors in many types of gastrointestinal tract cancer including cholangiocarcinoma (CCA). Alterations in bile acid concentrations may affect the pathogenesis of these different types of cancer. Our aim was to determine the bile acid profile in gallbladder bile from patients who underwent liver resection.

Liver fluke-induced hepatic oxysterols stimulate DNA damage and apoptosis in cultured human cholangiocytes.

Oxysterols are cholesterol oxidation products that are generated by enzymatic reactions through cytochrome P450 family enzymes or by non-enzymatic reactions involving reactive oxygen and nitrogen species. Oxysterols have been identified in bile in the setting of chronic inflammation, suggesting that biliary epithelial cells are chronically exposed to these compounds in certain clinical settings. We hypothesized that biliary oxysterols resulting from liver fluke infection participate in cholangiocarcinogenesis.

Hepatic free cholesterol accumulates in obese, diabetic mice and causes nonalcoholic steatohepatitis.

Background & Aims: Type 2 diabetes and nonalcoholic steatohepatitis (NASH) are associated with insulin resistance and disordered cholesterol homeostasis. We investigated the basis for hepatic cholesterol accumulation with insulin resistance and its relevance to the pathogenesis of NASH.

Methods: Alms1 mutant (foz/foz) and wild-type NOD.

Dietary cholesterol exacerbates hepatic steatosis and inflammation in obese LDL receptor-deficient mice.

Non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome, can progress to steatohepatitis (NASH) and advanced liver disease. Mechanisms that underlie this progression remain poorly understood, partly due to lack of good animal models that resemble human NASH. We previously showed that several metabolic syndrome features that develop in LDL receptor-deficient (LDLR-/-) mice fed a diabetogenic diet are worsened by dietary cholesterol.

Hepatic free fatty acids accumulate in experimental steatohepatitis: role of adaptive pathways.

Background/aims: We determined the effects of dietary lipid composition on steatohepatitis development with particular attention to the nature of lipid molecules that accumulate in the liver and pathways of hepatic triglyceride synthesis.

Methods: Mice were fed methionine and choline deficient (MCD) diets supplemented with 20% fat as lard (saturated) or olive oil (monounsaturated), for 3 weeks.

Results: Irrespective of dietary lipid composition, MCD-fed mice developed steatosis, ballooning degeneration and lobular inflammation.

Murine gallbladder epithelial cells can differentiate into hepatocyte-like cells in vitro.

We determined whether extrahepatic biliary epithelial cells can differentiate into cells with phenotypic features of hepatocytes. Gallbladders were removed from transgenic mice expressing hepatocyte-specific beta-galactosidase (beta-Gal) and cultured under standard conditions and under experimental conditions designed to induce differentiation into a hepatocyte-like phenotype. Gallbladder epithelial cells (GBEC) cultured under standard conditions exhibited no beta-Gal activity.

Gastric fluid bile concentrations and risk of Barrett's esophagus.

Patients with Barrett's esophagus are at high risk of progression to adenocarcinoma. A growing, but conflicting body of evidence implicates bile reflux as a contributor to Barrett's esophagus. To investigate whether duodenogastric reflux was associated with an increased risk of Barrett's esophagus, a case-control study of incident Barrett's esophagus was performed.

The production of oxysterols in bile by activated human leukocytes.

Oxysterols are naturally occurring intermediates in the conversion of cholesterol to bile acids, the major route for elimination of cholesterol. Additionally, they are important signaling agents, particularly in control of cholesterol synthesis; however, some species also are cytotoxic and carcinogenic. Oxysterols in plasma, contained in oxidized low-density lipoprotein, are strongly correlated with atherosclerosis.

Treatment of bile acid malabsorption using ileal stem cell transplantation.

Background: We hypothesized that ileal stem cell clusters transplanted into a segment of jejunum can be used to treat bile acid malabsorption.

Study Design: In adult Lewis rats, a 15-cm segment of jejunum was isolated with its blood circulation left intact and partially stripped of enterocytes using luminal high-velocity perfusions with 3mmol/L ethylenediamine tetra-acetic acid solutions. Continuity was restored by anastomosing the proximal and distal gut.

Origin of oxysterols in hepatic bile of patients with biliary infection.

Objectives: Oxysterols are ubiquitous in the body and are potential cytotoxic agents in addition to being metabolic regulators. Although bile contains high concentrations of cholesterol, oxysterol concentrations in bile and the effect of infection on oxysterol levels have not been measured, nor has their origin been studied. The purpose of this study was to determine if infection of the biliary tract was associated with increased concentrations of oxysterols in the bile and, if so, which oxysterols showed a significant change.

Biliary casts after orthotopic liver transplantation: clinical factors, treatment, biochemical analysis.

Objectives: Biliary casts develop in up to 18% of liver transplant recipients. Casts are associated with morbidity, graft failure, need for retransplantation, and mortality. Proposed etiological mechanisms include acute cellular rejection, ischemia, infection, and biliary obstruction.