Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015695 (fatty liver)
 13,941 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is not known whether obesity increases the risk for hepatocellular carcinoma (HCC) simply because it promotes cirrhosis, a general risk factor for HCC, or via some other mechanism that operates independently of cirrhosis. If the latter occurs, then hepatocyte hyperplasia, an early event during the neoplastic process, might begin before liver cirrhosis develops. Genetically obese, leptin-deficient ob/ob mice are models for nonalcoholic fatty liver disease (NAFLD), a type of liver disease that is strongly associated with obesity and type 2 diabetes. Similar to obese, diabetic patients, ob/ob mice have an increased incidence of HCC. However, unlike humans with NAFLD, they rarely, if ever, develop cirrhosis spontaneously. To determine whether the noncirrhotic livers of ob/ob mice with NAFLD exhibit hepatocyte hyperplasia, parameters of proliferation and apoptosis were compared in adult ob/ob mice and their healthy litter mates. Adult ob/ob mice have an increase in liver mass relative to body mass. This hepatomegaly cannot be explained solely by lipid accumulation and is accompanied by significant increases in hepatocyte proliferative activity (as evidenced by increased Erk activation, cell-cycle related gene expression, bromodeoxyuridine incorporation, and hepatic DNA content) with concomitant inhibition of hepatocyte apoptosis (as evidenced by decreased numbers of apoptotic hepatocytes, induction of several antiapoptotic mechanisms, and decreased activation of procaspase 3). Thus, liver hyperplasia is evident at the earliest stage of NAFLD in ob/ob mice, which supports the concept that obesity-related metabolic abnormalities, rather than cirrhosis, initiate the hepatic neoplastic process during obesity.
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PMID:Hepatic hyperplasia in noncirrhotic fatty livers: is obesity-related hepatic steatosis a premalignant condition? 1143 35

Advances in imaging technology and development of liver-specific contrast agents have significantly increased the role of radiology in the detection and characterization of processes diffusely involving the liver. Tailored magnetic resonance imaging (MRI) sequences allow an accurate detection of many storage and metabolic diseases, such as iron overload disorders and steatosis (fatty liver). Faster scanning techniques available with both computed tomography (CT) and MRI provide, by assessing contrast dynamics, sufficient information for the characterization of diffuse neoplastic and vascular disorders. Characteristic changes in attenuation on CT, signal intensity on MRI, and enhancing features can be used to diagnose specific diffuse diseases such as candidiasis, diffuse/multifocal hepatocellular carcinoma, and schistosomiasis. Although an overlap in imaging findings still exists, familiarity with the imaging features of uncommon disorders such as Wilson's disease, amyloidosis, and sarcoidosis may be diagnostic in the proper clinical setting. This review focuses on the current role of imaging in the detection and characterization of diffuse liver disorders. Recent developments that have amplified the role of noninvasive diagnostic evaluation of these conditions are especially highlighted.
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PMID:Imaging of diffuse liver disease. 1143 72

Hepatic steatosis and hepatocellular carcinoma (HCC) are common and serious features of hepatitis C virus (HCV) infection, and the core protein has been shown to play distinct roles in the pathogenesis. Here we report the direct interaction of HCV core protein with retinoid X receptor alpha (RXRalpha), a transcriptional regulator that controls many aspects of cell proliferation, differentiation, and lipid metabolism. The core protein binds to the DNA-binding domain of RXRalpha, leading to increase the DNA binding of RXRalpha to its responsive element. In addition, RXRalpha is activated in cells expressing the core protein as well as in the livers of the core-transgenic mice that would develop hepatic steatosis and HCC later in their lives. Using promoter genes of cellular retinol binding protein II (CRBPII) and acyl-CoA oxidase as reporters, we also show that the expression of the core protein enhances the transcriptional activity regulated by the RXRalpha homodimer as well as by the heterodimer with peroxisome proliferator activated receptor alpha. Furthermore, expression of the CRBPII gene is also up-regulated in the livers of HCV core-transgenic mice. In conclusion, these results suggest that modulation of RXRalpha-controlled gene expression via interaction with the core protein contributes to the pathogenesis of HCV infection.
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PMID:Interaction of hepatitis C virus core protein with retinoid X receptor alpha modulates its transcriptional activity. 1191 42

Alcoholic fatty liver is the earliest and most common response of the liver to alcohol and may be a precursor of more severe forms of liver injury. The mechanism by which ethanol causes fatty liver and liver injury is complex. We found that in both rat H4IIEC3 and McA-RH7777 hepatoma cell lines, ethanol induced transcription of a sterol regulatory element-binding protein (SREBP)-regulated promoter via increased levels of mature SREBP-1 protein. This effect of ethanol was blocked by addition of sterols. This effect is likely mediated by acetaldehyde, because the effect was only seen in cell lines expressing alcohol dehydrogenase, and inhibition of ethanol oxidation by 4-methylpyrazole blocked the effect in the hepatoma cells. Furthermore, the aldehyde dehydrogenase inhibitor cyanamide enhanced the effect of ethanol in the hepatoma cells. Consistent with these in vitro findings, feeding mice a low fat diet with ethanol for 4 weeks resulted in a significant increase in steady-state levels of the mature (active) form of SREBP-1. Activation of SREBP-1 by ethanol feeding was associated with increased expression of hepatic lipogenic genes as well as the accumulation of triglyceride in the livers. These finding suggest that metabolism of ethanol increased hepatic lipogenesis by activating SREBP-1 and that this effect of ethanol may contribute to the development of alcoholic fatty liver.
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PMID:Ethanol induces fatty acid synthesis pathways by activation of sterol regulatory element-binding protein (SREBP). 1203 55

The oxysterol-activated liver X receptor (LXR) provides a link between sterol and fatty acid metabolism; activation of LXR induces transcription of lipogenic genes. This study shows that induction of the lipogenic genes Srebp-1c, Fas, and Acc1 upon administration of the synthetic LXR agonist T0901317 to C57BL/6J mice (10 mg/kg/day, 4 days) is associated with massive hepatic steatosis along the entire liver lobule and a 2.5-fold increase in very low density lipoprotein-triglyceride (VLDL-TG) secretion. The increased VLDL-TG secretion was fully accounted for by formation of larger (129 +/- 9 nm versus 94 +/- 12 nm, a 2.5-fold increase of particle volume) TG-rich particles. Stimulation of VLDL-TG secretion did not lead to elevated plasma TG levels in C57BL/6J mice, indicating efficient particle metabolism and clearance. However, T0901317 treatment did lead to severe hypertriglyceridemia in mouse models of defective TG-rich lipoprotein clearance, i.e. APOE*3-Leiden transgenic mice (3.2-fold increase) and apoE-/- LDLr-/- double knockouts (12-fold increase). Incubation of rat hepatoma McA-RH7777 cells with T0901317 also resulted in intracellular TG accumulation and enhanced TG secretion. We conclude that, in addition to raising high density lipoprotein cholesterol concentrations, pharmacological LXR activation in mice leads to development of hepatic steatosis and secretion of atherogenic, large TG-rich VLDL particles.
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PMID:Stimulation of lipogenesis by pharmacological activation of the liver X receptor leads to production of large, triglyceride-rich very low density lipoprotein particles. 1209 30

The role of imaging in screening and evaluation of cirrhotic patients is to assess the extent of cirrhosis and portal hypertension (liver morphology, varices, ascites, vessel patency) and to detect hepatocellular carcinoma (HCC). Ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) have valuable roles, with catheter angiography usually reserved for specific problem solving. Ultrasonography is highly operator-dependent, and detection of focal masses is often difficult or impossible because of large patient body habitus and hepatic steatosis and fibrosis, which attenuate the ultrasound beam. For sonography, as well as CT and MRI, the use of intravenous contrast material with multiphasic imaging (arterial, portal venous, and delayed) is essential to accurately depict the morphology and hemodynamics of focal hepatic lesions. Computed tomography and MRI are highly accurate in diagnosis of large HCC but are much less accurate for lesions less than 2 cm in diameter. Many factors influence the choice and timing of imaging tests, including the etiology of the chronic liver disease, the elevation of serum tumor markers, and the availability and excellence of equipment and personnel. In our practice, helical multiphasic CT is obtained at least every 12 months, more frequently in patients judged to be at high risk for HCC.
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PMID:Use of radiologic techniques to screen for hepatocellular carcinoma. 1239 12

Nonalcoholic fatty liver disease, an entity that includes nonalcoholic steatohepatitis, is typically a benign, indolent condition. However, in a subset of patients, the clinical course may progress to advanced cirrhosis, end-stage liver disease, or hepatocellular carcinoma. Unfortunately, the pathogenesis, natural history, and potential therapies for these disorders remain poorly understood. Identifying patients who should be targeted for potential treatment remains difficult. Liver biopsy should be considered to assess the degree of hepatic inflammation and fibrosis, because physical examination findings, biochemical parameters, and the results of radiographic studies have been shown to correlate poorly with the severity of steatohepatitis and fibrosis. Although there is some evidence suggesting that obesity, diabetes mellitus, older age, and perhaps an aspartate transaminase:alanine aminotransaminase ratio higher than 1 may be predictors of more advanced fibrosis, histology remains the gold standard. Most patients with simple hepatic steatosis appear to follow a benign course and probably do not require aggressive therapy. Conversely, patients with steatohepatitis with extensive inflammation and fibrosis are the patients who are most likely to benefit from effective therapies. The most commonly recommended treatment is weight loss. Existing data suggest that rapid weight loss may promote hepatic inflammation and fibrosis; therefore, gradual weight loss should be recommended. Large, randomized, controlled trials evaluating the long-term histologic impact and clinical outcomes of weight loss strategies are lacking. Potentially promising pharmacologic therapies include insulin-sensitizing oral hypoglycemic agents such as metformin and the thiazolidenediols, antihyperlipidemic agents such as gemfibrozil or 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, vitamin E and other antioxidants, ursodeoxycholic acid, and betaine. As with weight loss, data regarding the efficacy of these pharmacologic options are limited. In addition, there are no widely accepted guidelines to help direct the clinician in the optimal use of these agents in patients with nonalcoholic fatty liver diseases.
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PMID:Therapeutic Options in Nonalcoholic Fatty Liver Disease. 1240 79

The incidence of hepatocellular carcinoma (HCC) in the United States is increasing, but the clinical characteristics of American patients with HCC have not been well described. The aims of this study were to determine the etiology of liver disease and short-term outcome among HCC patients presenting to a single center in the United States. One hundred five consecutive patients with HCC were studied; mean age was 59 years, 67% were men, and 76% were non-Hispanic white. The most common etiology of liver disease was hepatitis C (51%) and cryptogenic cirrhosis (29%). Half of the patients with cryptogenic cirrhosis had histologic or clinical features associated with nonalcoholic fatty liver disease (NAFLD). Fifty-three (50%) patients had HCC detected during surveillance (group I), whereas the remaining patients had symptomatic tumors (group II). Group I patients had smaller tumors (P =.01), were more likely to be eligible for surgical treatment (P =.005), and had a better median survival compared with patients in group II (P =.001). Patients with cryptogenic cirrhosis were less likely to have undergone HCC surveillance and had larger tumors at diagnosis. In conclusion, hepatitis C and cryptogenic liver disease are the most common etiologies of diseases in our patients with HCC. NAFLD accounted for at least 13% of the cases. Patients who underwent surveillance had smaller tumors and were more likely to be candidates for surgical or local ablative therapies. Because of the increasing incidence of NAFLD, further studies are needed to determine the risk of HCC in patients with NAFLD.
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PMID:NAFLD may be a common underlying liver disease in patients with hepatocellular carcinoma in the United States. 1244 58

Non alcoholic fatty liver disease (NAFLD) and its more agressive form, non alcoholic steatohepatitis (NASH) are entities that are becoming subject of interest of the medical community in general, especially because of the increased prevalence of diabetes and obesity in the world population. There is solid evidence linking NAFLD with the so called metabolic syndrome or syndrome X, to the point of accepting hepatic steatosis and its spectrum as one more element of the latter, along with diabetes, hipertension, hypertriglyceridemia and obesity. Insulin resistance seems to be the common link between these entities. Clinical evaluation of every patient with abnormal aminotransferase levels should take into account non alcoholic fatty liver and its spectrum, especially if the subject is obese or diabetic. Despite the important developments in the field of imaging, currenty the only way to differentiate NASH from simple NAFLD is by performing a liver biopsy, which should be discussed extensively with the patient. The prognosis of simple NAFLD is generally benign, but if there is fibrosis, ballooning of the hepatocytes, inflammation and Mallory bodies there is risk to progression to cirrhosis. Liver histology in NAFLD is indistinguishable from alcoholic hepatitis, although the clinical course is generally more benign. Despite this long and protracted clinical course, an important number of subjects have complications of cirrhosis including hepatocellular carcinoma, and many patients require a liver transplantation. There is no specific treatment for this condition, although every therapeutic regimen should include a gradual and supervised weight reduction, a balanced diet and exercise, as well as correction of precipitant factors. There is currently no specific pharmacologic treatment for NASH or NAFLD. Current body of evidence and some pilot studies suggest that the future might be concentrated in agents improving insulin resistance. Meanwhile, we should do our best to study the prevalence of NAFLD in our country and, when clinically pertinent, study histologically those patients with high risk of fibrosis.
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PMID:[Non-alcoholic fatty liver]. 1276 15

Although hepatitis C virus (HCV) is a well-known causative agent of hepatocellular carcinoma (HCC), the mechanism by which HCV induces HCC remains obscure. To elucidate the role of HCV in hepatocarcinogenesis, a model of hepatocyte injury was established using HCV core transgenic mice, which were developed using C57BL/6 mice transfected with the HCV core gene under control of the serum amyloid P component promoter. After 18-24 months, neither steatosis nor hepatic tumors were found in transgenic mice. The extent of hepatocyte injury and tumorigenesis were then examined in transgenic mice following repeated administration of carbon tetrachloride (CCl(4)) using various protocols (20%, 1/week; 10%, 2/week and 20%, 2/week). Serum alanine aminotransferase (ALT) levels did not differ among HCV core transgenic mice and non-transgenic littermates; however, after 40 weeks, hepatic adenomas preferentially developed in transgenic mice receiving 20% CCl(4) once weekly. Moreover, HCC was observed in transgenic mice receiving 2 weekly injections of a 20% solution of CCl(4), and was not observed in the non-transgenic control mice. In conclusion, the HCV core protein did not promote hepatic steatosis or tumor development in the absence of hepatotoxicity. However, the HCV core protein promoted adenoma and HCC development in transgenic mice following repeated CCl(4) administration. These results suggest that hepatotoxicity resulting in an increased rate of hepatocyte regeneration enhances hepatocarcinogenesis in HCV-infected livers. Furthermore, this experimental mouse model provides a valuable method with which to investigate hepatocarcinogenesis.
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PMID:Repeated hepatocyte injury promotes hepatic tumorigenesis in hepatitis C virus transgenic mice. 1290 92


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