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)

In recent years, the association between hyperlipidemia and the development of arteriosclerosis has been addressed in several studies. Rabbit models of hypertriglyceridemia (TGH) and postprandial hypertriglyceridemia (PHT) have been developed at the authors' institute. TGH rabbits manifest pathology similar to that of humans with TGH, such as xanthoma, in addition to atherosclerosis of arterioles. Furthermore, PHT rabbits show visceral obesity, insulin resistance, and impaired glucose tolerance, with pathologic features similar to those of the metabolic syndrome assumed to be the cause of human ischemic heart disease. This study was designed to investigate the histopathologic features of TGH and PHT rabbits. TGH rabbits showed advanced aortic atherosclerosis, accompanied by intimal thickening of coronary and renal arteries, fatty liver changes, and xanthoma. PHT rabbits demonstrated aortic intimal thickening and hepatic fatty degeneration. The results of this study suggest that TGH and PHT rabbits are useful animal models for studying human hyperlipidemia and metabolic syndrome and the cardiovascular diseases that result from these conditions.
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PMID:Pathologic findings in rabbit models of hereditary hypertriglyceridemia and hereditary postprandial hypertriglyceridemia. 1900 73

This study was designed to test the role of liver lipases in the degradation of liver triacylglycerols (TAG) and to determine the effect of dietary induced TAG accumulation in the liver on regulation of their lipolysis. Male Wistar rats were administered high-fat or high-sucrose diet for two weeks. Individual lipases (HL; TGH; LAL) were identified according to their different pH optimum. Administration of both diets resulted in liver TAG accumulation (HFD >>> HSD). The only lipase capable to hydrolyse intracellular TAG was LAL. On standard diet, LAL activity towards both endogenous and exogenous substrates was up-regulated in fasting and downregulated in fed state. The intensity of autophagy determined according to the LC3-II/LC3-I protein ratio followed a similar pattern. HFD led to an increase of this ratio, elevation of LAL activity in phagolysosomal fraction and abolishment of fasting/fed-dependent differences. LAL activity significantly correlated with ketogenesis in all groups (r = 0.86; P < 0.01). In the HFD group, we determined the enhanced release of lysosomal enzymes (glucuronidase, LAL) into the cytosol. Dgat-1 expression was up-regulated in HFD- and HSD-fed groups, which indicates increased FFA esterification. We demonstrated that LAL is a dominant enzyme involved in degradation of intracellular TAG in the liver and its translocation into the fraction of active (auto)phagolysosomes is stimulated by diet-induced TAG accumulation. Autophagy is stimulated under the same conditions as LAL and may represent the mechanism ensuring the substrate enzyme contact in autophagolysosomes. In fatty liver, destabilization of (auto)phagolysosomes may contribute to their susceptibility to further stress factors.
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PMID:The autophagy-lysosomal pathway is involved in TAG degradation in the liver: the effect of high-sucrose and high-fat diet. 2097 50

Non-alcoholic fatty liver disease can be attributed to the imbalance between lipogenesis and lipolysis in the liver. Alpha-lipoic acid has been shown to activate the 5'-AMP-activated protein kinase (AMPK) signalling pathway and to effectively inhibit the lipogenesis pathway in liver. However, whether alpha-lipoic acid stimulates lipolysis remains unclear. Recently, adipose triglyceride lipase (ATGL) was shown to be responsible for triacylglycerol hydrolase activity in cells. In the present study, we established a fatty liver cell model by incubating HepG2 cells in a high glucose (30mM glucose) and high fat (0.1mM palmitate) medium. We found that the activation of the AMPK signalling pathway induced ATGL protein expression and enhanced lipid hydrolysis. Similarly, treatment of the fatty liver cell model with alpha-lipoic acid reduced intracellular lipid accumulation in HepG2 cells, increased AMPK phosphorylation, and induced ATGL expression. We showed that insulin phosphorylates the transcription factor forkhead box O1 (FOXO1), which regulates ATGL expression and inhibits FOXO1 translocation into the nucleus. In contrast, alpha-lipoic acid dephosphorylated FOXO1 and reversed the nuclear exclusion of FOXO1. These data suggest that alpha-lipoic acid can effectively ameliorate intracellular lipid accumulation and induce ATGL expression through the FOXO1/ATGL pathway in liver cells. Thus, alpha-lipoic acid may be a potential therapeutic agent for treating fatty liver disease.
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PMID:Alpha-lipoic acid induces adipose triglyceride lipase expression and decreases intracellular lipid accumulation in HepG2 cells. 2281 8

Hepatic expression profiling has revealed miRNA changes in liver diseases, while hepatic miR-155 expression was increased in murine non-alcoholic fatty liver disease, suggesting that miR-155 might regulate the biological process of lipid metabolism. To illustrate the effects of miR-155 gain of function in transgenic mouse liver on lipid metabolism, transgenic mice (i.e., Rm155LG mice) for the conditional overexpression of mouse miR-155 transgene mediated by Cre/lox P system were firstly generated around the world in this study. Rm155LG mice were further crossed to Alb-Cre mice to realize the liver-specific overexpression of miR-155 transgene in Rm155LG/Alb-Cre double transgenic mice which showed the unaltered body weight, liver weight, epididymal fat pad weight and gross morphology and appearance of liver. Furthermore, liver-specific overexpression of miR-155 transgene resulted in significantly reduced levels of serum total cholesterol, triglycerides (TG) and high-density lipoprotein (HDL), as well as remarkably decreased contents of hepatic lipid, TG, HDL and free fatty acid in Rm155LG/Alb-Cre transgenic mice. More importantly, microarray data revealed a general downward trend in the expression profile of hepatic genes with functions typically associated with fatty acid, cholesterol and triglyceride metabolism, which is likely at least partially responsible for serum cholesterol and triglyceride lowering observed in Rm155LG/Alb-Cre mice. In this study, we demonstrated that hepatic overexpression of miR-155 alleviated nonalcoholic fatty liver induced by a high-fat diet. Additionally, carboxylesterase 3/triacylglycerol hydrolase (Ces3/TGH) was identified as a direct miR-155 target gene that is potentially responsible for the partial liver phenotypes observed in Rm155LG/Alb-Cre mice. Taken together, these data from miR-155 gain of function study suggest, for what we believe is the first time, the altered lipid metabolism and provide new insights into the metabolic state of the liver in Rm155LG/Alb-Cre mice.
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PMID:Overexpression of miR-155 in the liver of transgenic mice alters the expression profiling of hepatic genes associated with lipid metabolism. 2579 9

Nonalcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease in developed countries. NAFLD describes a wide range of liver pathologies from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. NASH is distinguished from simple steatosis by inflammation, cell death and fibrosis. In this study we found that mice lacking triacylglycerol hydrolase (TGH, also known as carboxylesterase 3 or carboxylesterase 1d) are protected from high-fat diet (HFD) - induced hepatic steatosis via decreased lipogenesis, increased fatty acid oxidation and improved hepatic insulin sensitivity. To examine the effect of the loss of TGH function on the more severe NAFLD form NASH, we ablated Tgh expression in two independent NASH mouse models, Pemt(-/-) mice fed HFD and Ldlr(-/-) mice fed high-fat, high-cholesterol Western-type diet (WTD). TGH deficiency reduced liver inflammation, oxidative stress and fibrosis in Pemt(-/-) mice. TGH deficiency also decreased NASH in Ldlr(-/-) mice. Collectively, these findings indicate that TGH deficiency attenuated both simple hepatic steatosis and irreversible NASH.
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PMID:Ces3/TGH Deficiency Attenuates Steatohepatitis. 2718 Oct 51