Prevention Of Fatty Liver Research Articles

Proteomic analysis of exosomes derived from fatty hepatocytes of grass carp.

Exosomes participate in intercellular communication by carrying proteins, messenger RNA, microRNAs, and non-coding RNA. Fatty liver is a common phenomenon in farmed fish, but there has been little study of fatty hepatocytes-derived exosomes. Here, we successfully isolated exosomes from hepatocytes of grass carp, named Exos (hepatocytes-derived exosomes) and OA-Exos (fatty hepatocytes-derived exosomes), from which 617 differentially expressed proteins were identified using liquid chromatography tandem mass spectrometry. Of these, 320 proteins were promoted and 297 proteins were restrained, which were gathered in biological processes and cellular components (cellular processes, cells, and intracellular structures). The results of kyoto encyclopedia of genes and genomes (KEGG) analysis revealed that the differential expression proteins were gathered in "carbohydrate transport and metabolism", "translation, ribosomal structure and biogenesis", "posttranslational modification, protein turnover, chaperones", and "intracellular trafficking, secretion, and vesicular transport". In addition, five differentially expressed exosomal proteins were further confirmed by parallel reaction monitoring, including 2-phospho-D-glycerate hydrolyase, cytochrome b5, fatty acid-binding protein domain-containing protein, metallothionein, and malate dehydrogenas, which were downregulated. These findings provided evidence that exosomes derived from fatty hepatocytes of grass carp may be biomarkers for the early diagnosis, treatment, and prevention of fatty liver in fishery development.

Impact of phytogenic formulation on performance and fatty liver disease of broiler chickens

This study was conducted to evaluate the effect of polyherbal (phytogenic) formulation (PHF: containing Acacia nilotica and Curcuma longa) on performance parameters, liver histopathology and prevention of fatty liver in broilers. 700 day-old chicks were randomly distributed to seven groups (10 replicates / group; 10 birds each), namely positive control (T1) fed with basal diet + choline chloride (CCL) 60% (1000g), negative control (T2) fed with high energy (5% increment), low protein (24% reduction), high cholesterol (2% increment) diet, T3 (T2 + PHF; 1000g-full cycle), T4 (T2 + PHF; 2000g-full cycle), T5 (T2 + CCL 60% (1000g-full cycle)), T6 (T5 + PHF; 1000g-grower and finisher stage), T7 (T5 + PHF; 2000g-finisher stage). Average daily gain (ADG; g), average daily feed intake (ADFI; g) and feed conversion ratio (FCR) were calculated at 1-14 days, 15-28 days, 29-42 days, and 1-42 days. Serum triglycerides analysis, gross and histopathological observations of liver morphology were performed for the samples of control and experimental groups on day 42. The performance parameters; ADG, ADFI, FCR, and liveability were found to be improved in all the groups as compared to the negative control group. However, better performance was observed in PHF (2000g) top-up group (during the finisher stage) as compared to the negative control group. Serum triglyceride levels were increased non-significantly as compared to the negative control indicating that more fat is mobilized from liver to serum. In addition, PHF supplementation at 2000g during the finisher phase had restored the liver tissue architecture as well as improved the liver score when compared to the negative control group. It is concluded that PHF (2000g/ton) during the finisher stage can be used as a top-up to improve the performance parameters as well as to prevent the fatty liver condition in broiler chickens.

Loss and gain of function of Grp75 or mitofusin 2 distinctly alter cholesterol metabolism, but all promote triglyceride accumulation in hepatocytes

In the liver, contact sites between the endoplasmic reticulum (ER) and mitochondria (named MAMs) may be crucial hubs for the regulation of lipid metabolism, thus contributing to the exacerbation or prevention of fatty liver. We hypothesized that tether proteins located at MAMs could play a key role in preventing triglyceride accumulation in hepatocytes and nonalcoholic fatty liver disease (NAFLD) occurrence. To test this, we explored the role of two key partners in building MAM integrity and functionality, the glucose-regulated protein 75 (Grp75) and mitofusin 2 (Mfn2), which liver contents are altered in obesity and NAFLD. Grp75 or Mfn2 expression was either silenced using siRNA or overexpressed with adenoviruses in Huh7 cells.Silencing of Grp75 and Mfn2 resulted in decreased ER-mitochondria interactions, mitochondrial network fusion state and mitochondrial oxidative capacity, while overexpression of the two proteins induced mirror impacts on these parameters. Furthermore, Grp75 or Mfn2 silencing decreased cellular cholesterol content and enhanced triglyceride secretion in ApoB100 lipoproteins, while their overexpression led to reverse effects. Cellular phosphatidylcholine/phosphatidylethanolamine ratio was decreased only upon overexpression of the proteins, potentially contributing to altered ApoB100 assembly and secretion. Despite the opposite differences, both silencing and overexpression of Grp75 or Mfn2 induced triglyceride storage, although a fatty acid challenge was required to express the alteration upon protein silencing. Among the mechanisms potentially involved in this phenotype, ER stress was closely associated with altered triglyceride metabolism after Grp75 or Mfn2 overexpression, while blunted mitochondrial FA oxidation capacity may be the main defect causing triglyceride accumulation upon Grp75 or Mfn2 silencing. Further studies are required to decipher the link between modulation of Grp75 or Mfn2 expression, change in MAM integrity and alteration of cholesterol content of the cell.In conclusion, Grp75 or Mfn2 silencing and overexpression in Huh7 cells contribute to altering MAM integrity and cholesterol storage in opposite directions, but all promote triglyceride accumulation through distinct cellular pathways. This study also highlights that besides Mfn2, Grp75 could play a central role in hepatic lipid and cholesterol metabolism in obesity and NAFLD.

Long-term treatment with metformin in the prevention of fatty liver in Zucker diabetic fatty rats

BackgroundTreatment with metformin, the biguanide of hepatic insulin sensitizer, in patients with non-alcoholic fatty liver disease (NAFLD) has been reported with contradictory findings regarding the effectiveness on blood lipids and liver histology. In this study, we aimed to explore the preventive effects of metformin on NAFLD in Zucker diabetic fatty (ZDF) rats.MethodsMale ZDF rats and Zucker lean rats aged 4–8 weeks were subjected to vehicle or metformin treatment for 6 months. Liver cDNA microarray assay, and protein semiquantitative and histological examinations were performed.ResultsData demonstrated that ZDF rats developed hyperglycemia, hyperlipidemia, liver deficiency and hepatocyte degeneration. The metformin treatment significantly reduced post-load blood glucose levels, but not blood lipid profiles or liver enzyme levels. Hepatocyte degeneration was not attenuated after the treatment. The metformin-treated ZDF rats showed activation of AMP-activated protein kinase by Western blot and overexpression of cytochrome c oxidase by immunofluorescent microscopy. Gene expression microarray assay demonstrated that a panel of genes participating in glucose and lipid metabolisms were changed in the ZDF rats, and most of the altered genes involved in glucose and cholesterol metabolisms, but not those in fatty acid metabolisms, were corrected by the metformin treatment. No genes associated with inflammation, apoptosis, fibrosis, or cell death were overexpressed in the metformin-treated ZDF rats.ConclusionsThese results suggest that long-term metformin treatment presents no preventive effect for NAFLD in ZDF rats.

Monascin and Ankaflavin Have More Anti-atherosclerosis Effect and Less Side Effect Involving Increasing Creatinine Phosphokinase Activity than Monacolin K under the Same Dosages

Monacolin K has long been considered a major effective component in the hypolipidemic functions of Monascus . Monacolin K also serves as a well-known hypolipidemic medication, but its side effect myopathy is a concern. Monascin and ankaflavin, the yellow pigments produced by Monascus species, have been proven to possess hypolipidemic functions; however, no studies have compared the hypolipidemic effects of monascin, ankaflavin, and monacolin K under the same dosages. In this study, the equal dosages of monascin, ankaflavin, and monacolin K were oral administrated to hamsters fed a high cholesterol diet for 6 weeks. Comparison of the displayed hypolipidemic and anti-atherosclerosis effects was performed, in addition to an investigation into the inducement of side effect. The results indicated that monascin and ankaflavin were similar to monacolin K in significantly reducing total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) levels in serum and lipid plaque (p < 0.05) in the heart aorta. In addition, ankaflavin achieved the effects of serum TC and TG reduction, with no significant difference as compared to those effects of monacolin K (p > 0.05). However, as compared to monacolin K, ankaflavin possessed more significant effects on the prevention of fatty liver and lipid plaque accumulation in heart aorta. More importantly, monascin significantly enhanced high-density lipoprotein cholesterol (HDL-C) concentrations, while monacolin K displayed the opposite effect. Regarding the side effect, monacolin K also raised elevated creatinine phosphokinase (CPK) activity, which was highly correlated with rhabdomyolysis development, while monascin and ankaflavin did not induce such a side effect. In conclusion, MS and AK had the potential to be developed as hypolipidemic agents without rhabdomyolysis development.

Putative Mechanisms of Environmental Chemical–Induced Steatosis

Liver disease is a major health issue characterized by several pathological changes, with steatosis (fatty liver) representing a common initial step in its pathogenesis. Steatosis is of critical importance because prevention of fatty liver can obviate downstream pathologies of liver disease (eg, fibrosis). Recent studies have shown a strong correlation between chemical exposure and steatosis. The work described here identifies chemicals on the US Environmental Protection Agency's Integrated Risk Information System (IRIS) that induce steatosis and investigates putative mechanisms by which these chemicals may contribute to this pathological condition. Mitochondrial impairment, insulin resistance, impaired hepatic lipid secretion, and enhanced cytokine production were identified as potential mechanisms that could contribute to steatosis. Taken together, this work is significant because it identifies multiple mechanisms by which environmental chemicals may cause fatty liver and expands our knowledge of the possible role of environmental chemical exposure in the induction and progression of liver disease.

Consumption of dehydrated Opuntia ficus Indica (nopal) prevents the development of fatty liver by modifying hepatic lipid metabolism in obese Zucker fa/fa rats

Opuntia ficus indica (nopal), a plant rich in bioactive compounds, has been widely used in the traditional Mexican medicine to treat diabetes. Therefore in the present study, we investigated the effect of nopal consumption in the prevention of fatty liver in obese Zucker rats.Six weeks old male Zucker (fa/fa) rats (n=12 per group) were fed with a control diet (AIN‐93G; C) or C+ Nopal for 7 weeks. After 7 weeks of dietary treatment, rats fed C+nopal decreased by 50% hepatic triglycerides with respect to control and reduced hepatomegaly and macrovesicular steatosis. In addition, increased serum levels of adiponectin, mRNA expression of genes involved in lipid oxidation (PPARα, CPT1 and ACOX) and lipid export (MTTP and PLTP), hepatic CPT1 and MTTP protein levels. Furthermore, rats fed C+nopal decreased postprandial serum insulin levels; increased liver pAkt/Akt ratio in the postprandial state and significantly decreased serum ALT and AST levels.This study shows that nopal consumption prevents the development of fatty liver in obese Zucker rats by increasing fatty acid oxidation and VLDL synthesis,, improving liver insulin signaling. Supported by Grupo Produce DF 2010 (to NT)Grant Funding Source: Produce

味噌の給与によるウシの脂肪肝予防効果に関する研究

[in Japanese]

Mulberry extract inhibits oleic acid‐induced lipid accumulation via reduction of lipogenesis and promotion of hepatic lipid clearance

Mulberries are a traditional edible food used to treat hepatic disease. The anti-obesity and hypolipidemic effects of mulberry water extracts (MWE) have attracted increasing interest. In the present study, MWE were assessed for their hepatic lipid-lowering potential when administered in fatty acid overload conditions in HepG2 cells. We found that MWE significantly reduced lipid accumulation, suppressed fatty acid synthesis, and stimulated fatty acid oxidation. Furthermore, MWE also inhibited acetyl coenzyme A carboxylase activities by stimulating adenosine monophosphate-activated protein kinase (AMPK). MWE attenuated the expression of sterol regulatory element-binding protein-1 (SREBP-1) and its target molecules, such as fatty acid synthase. Similar results were also measured in the expressions of enzymes involved in triglyceride and cholesterol biosyntheses including glycerol-3-phosphate acyltransferase, 3-hydroxy-3-methylglutaryl-CoA reductase, and SREBP-2. In contrast, the lipolytic enzyme expression of peroxisome proliferator activated receptor α and carnitine palmitoyltransferase-1 were increased. Our study suggests that the hypolipidemic effects of MWE occur via phosphorylation of AMPK and inhibition of lipid biosynthesis. Therefore, the mulberry extract may be active in the prevention of fatty liver.

Transgenic expression of CYP7A1 in the liver prevents high fat diet‐induced obesity and insulin resistance in mice

Bile acid‐activated FXR plays a key role in lipid, glucose, drug and energy metabolism. Cholesterol 7á‐hydroxylase (CYP7A1) catalyzes the rate‐limiting step in the conversion of cholesterol into bile acids in the liver. The mechanism of bile acid‐mediated regulation of glucose and lipid metabolism remains unclear. The objective of this study is to investigate the role of CYP7A1 in the prevention of fatty liver, obesity and diabetes. Transgenic mice carrying an ApoE3‐CYP7A1 coding sequence (Cyp7a1‐tg) were used to study high fat diet (HFD) induced obesity, fatty liver, and insulin resistance. Cyp7a1‐tg mice had a ~ 3‐fold higher bile acid pool size than wild type mice. When fed a HFD, Cyp7a1‐tg mice were resistant to weight gain, fatty liver and insulin resistance, and had decreased fat mass and hepatic triglycerides and cholesterol content than wild type mice. Cyp7a1‐tg mice showed increased hepatic VLDL secretion but maintained plasma triglyceride and cholesterol homeostasis. Indirect calorimetry revealed that HFD fed Cyp7a1‐tg mice had increased energy expenditure and higher respiratory quotient than wild type mice. This study suggests that maintaining bile acid homeostasis is important in regulating whole body lipid, glucose and energy homeostasis. Bile acids and derivative may be potential therapeutic agents for treating metabolic disorders such as fatty liver diseases, obesity and diabetes in humans.

Theaflavins attenuate hepatic lipid accumulation through activating AMPK in human HepG2 cells

Black tea is one of the world's most popular beverages, and its health-promoting effects have been intensively investigated. The antiobesity and hypolipidemic effects of black tea have attracted increasing interest, but the mechanisms underlying these phenomena remain unclear. In the present study, the black tea major component theaflavins were assessed for their hepatic lipid-lowering potential when administered in fatty acid overload conditions both in cell culture and in an animal experimental model. We found that theaflavins significantly reduced lipid accumulation, suppressed fatty acid synthesis, and stimulated fatty acid oxidation. Furthermore, theaflavins also inhibited acetyl-coenzyme A carboxylase activities by stimulating AMP-activated protein kinase (AMPK) through the LKB1 and reactive oxygen species pathways. These observations support the idea that AMPK is a critical component of decreased hepatic lipid accumulation by theaflavin treatments. Our results show that theaflavins are bioavailable both in vitro and in vivo and may be active in the prevention of fatty liver and obesity.

Prevention of Fatty Liver in Transition Dairy Cows by Subcutaneous Injections of Glucagon

The main objective of this study was to test the extent to which injecting glucagon subcutaneously for 14 d beginning at d 2 postpartum would prevent fatty liver development in transition dairy cows. Twenty-four multiparous Holstein cows were fed 6kg of cracked corn in addition to their standard diet during the last 30 d of a dry period to induce postpartum development of fatty liver. Glucagon at either 7.5 or 15mg/d or saline (control) was injected subcutaneously 3 times daily for 14 d beginning at d 2 postpartum. Glucagon at 15mg/d prevented liver triacylglycerol accumulation in postpartum dairy cows. Glucagon at 7.5mg/d showed potential for fatty liver prevention. Glucagon increased concentration of plasma glucose and insulin and decreased plasma nonesterified fatty acid concentrations. No effects of glucagon were detected on plasma β-hydroxybutyrate concentrations. Glucagon affected neither feed intake nor milk production. Moreover, milk composition was not altered by glucagon. Milk urea N concentrations decreased, and plasma urea N concentrations tended to decrease during glucagon administration, indicating that glucagon may improve protein use. Liver glycogen concentrations were not affected by glucagon. No significant differences in body condition scores were detected among treatments throughout the study. These results indicate that subcutaneous glucagon injections can prevent fatty liver in transition dairy cows without causing major production and metabolite disturbances.

679 Prevention of fatty liver in P66SHC deficient mice chronically fed with alcohol

679 Prevention of fatty liver in P66SHC deficient mice chronically fed with alcohol

Effects of dietary water-soluble rice bran, phytic acid and myo-inositol on prevention of fatty liver in rats fed DDT.

Effects of dietary water-soluble rice bran, phytic acid and myo-inositol on prevention of fatty liver in rats fed DDT.

Efficacy of Sodium Borate in the Prevention of Fatty Liver in Dairy Cows

The effects of sodium borate (100 mg/kg body weight, PO, 15 days) from a month before expected calving until a month after calving were evaluated in dairy cows susceptible to fatty liver. Cows received either sodium borate (n = 13) or no treatment (n = 10). All cows had mild fatty livers and increased plasma triglycerides and very low density lipoprotein (VLDL) concentrations at the beginning of the experiment. The control group of cows developed significant fatty liver after calving, and 2 of them had severe fatty liver associated with clinical and biochemical abnormalities. There were no clinicopathological signs related to sodium borate administration. Serum triglycerides and VLDL concentrations before calving decreased significantly at calving and after calving in controls, and they were within the normal range only after calving. There were significant alterations during the experiment in some hematological and chemical variables between groups, within period, but they were within the normal range. Unlike treated cows, serum triglycerides and VLDL concentrations correlated with liver fat content after calving in untreated cows. Our results document that sodium borate decreases the degree of fatty liver in dairy cows during early lactation.

オロチン酸投与によるラット脂肪肝に対する大麦焼酎粕の抑制効果

オロチン酸投与によるラット脂肪肝に対する大麦焼酎粕の抑制効果

Inhibitory effects of chondroitin sulfate prepared from salmon nasal cartilage on fat storage in mice fed a high-fat diet

Chondroitin sulfate is an acidic polymer consisting of repeating D-glucuronic acid and D-N-acetylgalactosamine units, and the N-acetylgalactosamine is substituted with the sulfate at either the 4' or 6' position, with approximately one sulfate being present per disaccharide unit. The present study assessed the effects of chondroitin sulfate on the activity of pancreatic lipase and lipid uptake into brush border membrane vesicles of the rat small intestine in vitro, and on the degree of fat storage induced in mice by the oral administration of a high-fat diet for 8 weeks. Experiments were carried out to clarify whether or not chondroitin sulfate inhibited pancreatic lipase activity in assay systems using triolein emulsified with phosphatidylcholine or gum arabic. In addition, the effects of chondroitin sulfate on lipid absorption by brush border membrane vesicles were examined. Moreover, mice were fed a high-fat diet and treated with chondroitin sulfate for 8 weeks. Chondroitin sulfate dose-dependently inhibited the pancreatic lipase activity in an assay system using triolein emulsified with phosphatidylcholine. In addition, chondroitin sulfate inhibited the palmitic acid uptake into the brush border membrane vesicles of the rat jejunum. Chondroitin sulfate caused the reduction of body weight and parametrial adipose tissue weight, and prevention of fatty liver and hyperlipidemia in mice fed a high-fat diet. The reduction of fat storage and the antihyperlipidemic action of chondroitin sulfate might be due to the inhibition of small intestinal absorption of dietary fat through the inhibition of pancreatic lipase activity and fatty acid uptake through brush border membrane.

Prevention of fatty liver and maintenance of systemic valine depletion using a newly developed dual infusion system.

Valine-depleted amino acid imbalance, while having a suppressive effect on tumor growth, may induce fatty liver. We administered a valine-depleted total parenteral nutrition (TPN) solution by the central venous route to non-tumor-bearing rats and examined the time course of the development of fatty liver. In an attempt to prevent this condition, we administered a continuous infusion of low concentrations of valine via the portal vein simultaneously with administration of central venous valine-depleted nutrition for 4 days. A marked accumulation of triglyceride was observed in the liver on day 4 of the administration of valine-depleted nutrition. It is speculated that such accumulation is the cause of fatty liver. The level of valine in the peripheral blood began to decrease soon after administration was begun and resulted in a state of systemic valine deficiency. Rats given 25% or more of the valine concentration in the standard TPN solution via the portal vein simultaneously with the administration of central venous valine-depleted nutrition, had a triglyceride level similar to that of the control group. The group given 50% or less of the valine concentration had a level of valine in the peripheral blood as low as that of the valine-depleted group, indicating the maintenance of a valine-deficient state. Administration of low concentrations of valine via the portal vein simultaneous with central venous administration of valine-depleted TPN solution may prevent fatty liver.

Fatty Liver in Dairy Cows

An increase in liver fat concentration during the peripartum period is extremely common in dairy cows and, to some degree, is probably normal. When severe, it is associated with clinical problems including increased morbidity and mortality and reduced breeding efficiency. Fatty liver develops when serum NEFA concentrations rise and hepatic uptake of NEFA exceeds the liver's ability to synthesize and secrete lipoproteins. In most cases, hepatic lipid accumulation appears to commence prepartum, in association with rising serum NEFA concentrations and declining serum lipoprotein concentrations. Commonly used clinicopathologic tests of liver function do not yield clearly abnormal results except in animals with extremely high concentrations of liver fat. Clinically useful estimates of hepatic lipid concentration can be obtained in the field by determining the buoyancy of needle biopsy samples in liquids of various specific gravities. Clinically ill animals with liver fat concentrations of greater than 35 per cent by weight have a poor prognosis, and those that do survive will have a protracted convalescence. Treatment of dairy cows with clinical fatty liver should be aimed at reducing further adipose lipid mobilization and promoting hepatic lipoprotein synthesis; however, protocols for therapy have not as yet been evaluated critically. Prevention of fatty liver is more rewarding than treatment. Dry cows should be maintained in a moderately fat condition and fed high-quality, palatable feeds in amounts necessary to met or slightly exceed their energy requirements. Free-choice feeding of high-energy feeds should be avoided in late lactation and during the nonlactating period.

P-8-19 Effectiveness of polyenephosphatidylcholine (PC) in prevention of fatty liver in the monosodium glutamate (MSG)-induced obese rats

P-8-19 Effectiveness of polyenephosphatidylcholine (PC) in prevention of fatty liver in the monosodium glutamate (MSG)-induced obese rats