Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020473 (hyperlipidemia)
 15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a nuclear receptor that mediates the antidiabetic effects of thiazolidinediones. PPAR gamma is present in adipose tissue and becomes elevated in fatty livers, but the roles of specific tissues in thiazolidinedione actions are unclear. We studied the function of liver PPAR gamma in both lipoatrophic A-ZIP/F-1 (AZIP) and wild type mice. In AZIP mice, ablation of liver PPAR gamma reduced the hepatic steatosis but worsened the hyperlipidemia, triglyceride clearance, and muscle insulin resistance. Inactivation of AZIP liver PPAR gamma also abolished the hypoglycemic and hypolipidemic effects of rosiglitazone, demonstrating that, in the absence of adipose tissue, the liver is a primary and major site of thiazolidinedione action. In contrast, rosiglitazone remained effective in non-lipoatrophic mice lacking liver PPAR gamma, suggesting that adipose tissue is the major site of thiazolidinedione action in typical mice with adipose tissue. Interestingly, mice without liver PPAR gamma, but with adipose tissue, developed relative fat intolerance, increased adiposity, hyperlipidemia, and insulin resistance. Thus, liver PPAR gamma regulates triglyceride homeostasis, contributing to hepatic steatosis, but protecting other tissues from triglyceride accumulation and insulin resistance.
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PMID:Liver peroxisome proliferator-activated receptor gamma contributes to hepatic steatosis, triglyceride clearance, and regulation of body fat mass. 1280 74

The field of new lipid-lowering drug research is very active, with researchers, looking to make the currently available drugs more powerful and safer, and to develop new classes of drugs. Among the statins, development has gone the farthest for rosuvastatin and pitavastatin. Colesevelam is a new bile acid sequestrant with a better digestive tolerance. Among the new classes of drugs, the most promising molecules are the cholesterol absorption inhibitors--with ezetimibe as the first in line--and the PPAR-alpha and PPAR-gamma activators. Among the other classes, the acyl-CoA:cholesterol acyltransferase (ACAT) inhibitors, microsomal triglyceride transfer protein (MTP) inhibitors, cholesteryl ester transfer protein (CETP) inhibitors, and ileal bile acid transporter inhibitors, have to be mentioned. In most of the cases, those new compounds are being developed mainly as a combined treatment with statins. However, these combination therapies differ depending on the lipid abnormalities of the patient. The statin-ezitimibe and the statin-bile acid sequestrant combinations have been the most studied treatments in pure hypercholesterolaemia. On another hand, the statin-PPAR-alpha and -gamma activator combination were the first to be developed for patients with combined hyperlipidaemia or type 2 diabetes mellitus. However, the clinical benefit of ACAT or CETP inhibitors remains to be determined and the development of MTP inhibitors has been restricted so far, because of problems of digestive intolerance and hepatic steatosis. Finally, the discovery of new specific lipoprotein receptors, such as the ABCA1 and SRB1 receptors, means that we can work towards developing new potential targets for pharmacological intervention.
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PMID:[New antilipemics: prospects]. 1282 7

Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by marked lack of body fat since birth, which results in striking muscular appearance. Patients develop extreme insulin resistance and its complications, such as diabetes, hyperlipidemia and fatty liver. Mutations in the BSCL2 (which encodes seipin, a protein of unknown function) and AGPAT2 (which encodes 1-acylglycerol-3-phosphate O-acyltransferase 2) genes have been reported in patients with CGL. AGPAT2 is a key enzyme involved in triglyceride and phospholipid biosynthesis and, thus, the discovery of AGPAT2 mutations has heightened interest in the biochemical pathways of triglyceride synthesis and their implications in human physiology and in the pathophysiology of obesity, lipodystrophies and other adipose tissue disorders. All enzymes involved in triglyceride synthesis, including AGPAT, have several known isoforms encoded by different genes. Assuming different substrate specificities of these enzymes, the human body might have many forms of triglycerides and phospholipids. Here, we discuss the significance of these in energy storage, in addition to the normal functioning of cell membranes.
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PMID:Congenital generalized lipodystrophy: significance of triglyceride biosynthetic pathways. 1282 27

Tamoxifen is a potent antagonist of estrogen, and hepatic steatosis is a frequent complication in adjuvant tamoxifen for breast cancer. Impaired hepatic FA beta-oxidation in peroxisomes, microsomes, and mitochondria results in progression of massive hepatic steatosis in estrogen deficiency. This impairment, although latent, is potentially serious: About 3% of the general population in the United States is now suffering from nonalcoholic steatohepatitis associated with obesity and hyperlipidemia. Therefore, in the present study we tried to restore impaired hepatic FA beta-oxidation by administering a novel statin, pitavastatin, to aromatase-deficient (Ar-/-) mice defective in intrinsic estrogen synthesis. Northern blot analysis of Ar-/- mice liver revealed a significant restoration of mRNA expression of essential enzymes involved in FA beta-oxidation such as very long fatty acyl-CoA synthetase in peroxisome, peroxisomal fatty acyl-CoA oxidase, and medium-chain acyl-CoA dehydrogenase. Severe hepatic steatosis observed in Ar-/- mice substantially regressed. Consistent findings were obtained in the in vitro assays of FA beta-oxidation activity. These findings demonstrate that pitavastatin is capable of restoring impaired FA beta-oxidation in vivo via the peroxisome proliferator-activated receptor-alpha-mediated signaling pathway and is potent enough to ameliorate severe hepatic steatosis in mice deficient in intrinsic estrogen.
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PMID:Pitavastatin ameliorates severe hepatic steatosis in aromatase-deficient (Ar-/-) mice. 1288 Jan 7

Nonalcoholic fatty liver disease is a condition gaining increasing recognition as a cause of cirrhosis and end-stage liver disease. The condition appears identical to alcoholic liver disease histologically, yet occurs in patients with negligible alcohol intake. Nonalcoholic fatty liver disease covers a spectrum of diseases ranging from simple fatty deposition in the liver to fat and inflammation and finally to fibrosis and cirrhosis. Conditions most frequently found in association with nonalcoholic fatty liver disease include obesity, Type 2 diabetes, and hyperlipidemia. Although the exact etiology of nonalcoholic fatty liver disease is not clear, insulin resistance is thought to play an important factor. Patients typically present with asymptomatic serum aminotransferase elevations of 2-3 times normal. Symptoms may include fatigue and abdominal pain. The clinical course is difficult to predict due to a lack of research in the natural history of the disease. It is known a percentage of patients progress to end-stage liver disease and may require liver transplantation. No medical treatment has been found to be totally effective. Patients who are overweight or obese should be encouraged in gradual weight reduction that has been associated with improvement in liver test abnormalities.
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PMID:Nonalcoholic Fatty liver disease. 1292 Apr 29

Recent studies indicate that some patients with nonalcoholic fatty liver have ongoing liver injury that may progress from steatosis to steatohepatitis or fibrosis. The present study was designed to clarify the clinical features of liver dysfunction observed in the course of workplace physical check-ups in relation to multiple risk factor syndrome including obesity, hyperlipidemia, hypertension, and impaired glucose tolerance, and to clarify the involvement of aldehyde dehydrogenase 2 (ALDH2) and beta(3)-adrenergic receptor (beta3-AR) gene polymorphisms in elevation of liver enzymes. One hundred forty-eight male workers 35 years of age were enrolled. They were requested to answer questionnaires about drinking and smoking habits, and underwent urinalysis, physical and peripheral blood examinations, blood chemistry, electrocardiogram and chest x-rays. The genotypes of ALDH2 and beta3-AR were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The subjects were divided into active ALDH2 or inactive ALDH2 groups. They were also divided into 2 groups according to the beta3-AR genotype. The relationships between ALDH2 and beta3-AR gene polymorphism and the results of the physical examination including liver function tests were analyzed. The subjects were also divided according to the number of components of metabolic syndrome. The prevalence of elevated alanine aminotransferase (ALT) level increased with the accumulation of components of metabolic syndrome. Active ALDH2 was associated with elevated ALT level to a greater degree than beta3-AR polymorphism. Among those with normal body mass index (BMI), the genotypes of ALDH2 and beta3-AR were strongly associated with elevated ALT level. Logistic regression analysis revealed that BMI, triglyceride level, and ALDH2 genotype were associated with ALT elevation. In conclusion, evaluating the genotype of ALDH2 and beta3-AR may assist in predicting and preventing the development of fatty liver which may be related to multiple risk factor syndrome.
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PMID:Aldehyde dehydrogenase 2 and beta3-adrenergic receptor gene polymorphisms: their association with elevated liver enzymes and metabolic syndrome. 1450 13

A 56-year old Japanese female was admitted to our hospital because of the increased levels of serum AST, ALT, and gamma-GTP. She was diagnosed with systemic lupus erythematosus in September, 1996 and had been on a regular glucocorticoid therapy since then. Abdominal ultrasonography showed the mild fatty liver, and hepatic histopathology revealed a typical and remarkable steatohepatitis, a remarkable neutrophil infiltration, and Mallory bodies. Because she had no history of alcohol-drinking, diagnosis of non-alcoholic steatohepatitis (NASH) was made. Treatment was started with a low-calorie diet, bed-rest, and an oral administration of alpha-tocopherol and bezafibrate with favorable effects on her serum levels of AST, ALT, gamma-GTP, and LDH. When a patient on a glucocorticoid therapy shows signs of fatty liver, diabetes mellitus, hyperlipidemia, an insulin resistance, NASH should be considered as one of the differential diagnosis. This is particularly important since proper therapy with a low-calorie diet and drugs with anti-oxidant activities improve this potentially progressive disease before resulting in liver cirrhosis and hepatic carcinoma.
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PMID:[Systemic lupus erythematosus with steroid induced non-alcoholic steatohepatitis: a case report]. 1459 60

Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a nuclear receptor, which controls adipocyte differentiation. We targeted with homologous recombination the PPAR gamma 2-specific exon B, resulting in a white adipose tissue knockdown of PPAR gamma. Although homozygous (PPAR gamma hyp/hyp) mice are born with similar weight as the WT mice, the PPAR gamma hyp/hyp animals become growth retarded and develop severe lipodystrophy and hyperlipidemia. Almost half of these PPAR gamma hyp/hyp mice die before adulthood, whereas the surviving PPAR gamma hyp/hyp animals overcome the growth retardation, yet remain lipodystrophic. In contrast to most lipodystrophic models, the adult PPAR gamma hyp/hyp mice only have mild glucose intolerance and do not have a fatty liver. These metabolic consequences of the lipodystrophy are relatively benign because of the induction of a compensatory gene expression program in the muscle that enables efficient oxidation of excess lipids. The PPAR gamma hyp/hyp mice unequivocally demonstrate that PPAR gamma is the master regulator of adipogenesis in vivo and establish that lipid and glucose homeostasis can be relatively well maintained in the absence of white adipose tissue.
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PMID:Compensation by the muscle limits the metabolic consequences of lipodystrophy in PPAR gamma hypomorphic mice. 1460 33

Liver steatosis is a common human disease, most often caused by long-term alcohol consumption. Non-alcoholic steatohepatitis (NASH) is characterized by similar histopathological features to those observed in alcoholic liver disease, but occurs in the absence of significant alcohol consumption. Several aetiological factors contribute to NASH: obesity, type 2 diabetes mellitus, hyperlipidaemia, pregnancy, different chemical intoxications, parenteral nutrition, jejeuno-ileal bypass, chronic inflammatory bowel disease, nutritional protein deficiency and congenital metabolic disorders. Biochemically, oxidative stress and lipid peroxidation and their ensuing damage are implicated in the pathogenesis of NASH and alcoholic steatohepatitis (probably resulting from free fatty acids in the mitochondria, and induction of the cytochrome P450 isoform CYP2E1 in hepatocytes and Kupffer's cells). This paper deals with the pathomechanisms, clinical findings and currently available therapies for NASH. The potential use of metadoxine in the treatment of NASH is also discussed.
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PMID:A new approach to drug therapy in non-alcoholic steatohepatitis (NASH). 1470 19

Hepatic steatosis is a recognized feature of hepatitis C viral infection, particularly in genotype 3. The demographics and the associations contributing to moderate to severe steatosis in genotype 3 are not very well studied. The aim of this study is to determine the demographics and association of steatosis with fibrosis, obesity, diabetes, lipid levels, and risk factors among patients with hepatitis C virus (HCV) genotype 3. Two hundred ninety-three consecutive HCV patients (genotype 1, n = 218; genotype 2, n = 43; genotype 3, n = 32) at our institution were studied retrospectively. Demographic information such as height, weight, genotype, risk factors, serum cholesterol and triglyceride, and liver biopsy was collected. Steatosis was graded using the Brunt classification. HCV genotype 3-infected patients were younger (P < 0.04) and had lower serum cholesterol levels (P < 0.02) compared to nongenotype 3 patients. Moderate to severe steatosis was more prevalent in HCV genotype 3 patients (P < 0.001) with intravenous drug abuse as a risk factor (P = 0.04). Genotype 3 was the independent predictor of steatosis in all patients. There was no statistical association between grade of steatosis and body mass index, fibrosis, necroinflammation, or hyperlipidemia when only HCV genotype 3 patients were included in the multivariate logistic model. Hepatic steatosis is a feature of genotype 3. Patients with HCV genotype 3 are younger and have lower serum cholesterol levels. Genotype 3 is the independent predictor for steatosis in HCV patients. HCV genotype 3 patients with moderate to severe steatosis are more likely to have intravenous drug use as a risk factor.
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PMID:Hepatic steatosis in hepatitis C virus genotype 3 infection: does it correlate with body mass index, fibrosis, and HCV risk factors? 1499 30


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