Decrease In Hepatic Triglyceride Content Research Articles

ADAR2 deficiency ameliorates non-alcoholic fatty liver disease and muscle atrophy through modulating serum amyloid A1.

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength, which is commonly associated with NAFLD. Adenosine-to-inosine editing, catalysed by adenosine deaminase acting on RNA (ADAR), is an important post-transcriptional modification of genome-encoded RNA transcripts. Three ADAR gene family members, including ADAR1, ADAR2 and ADAR3, have been identified. However, the functional role of ADAR2 in obesity-associated NAFLD and sarcopenia remains unclear. ADAR2+/+/GluR-BR/R mice (wild type [WT]) and ADAR2-/-/GluR-BR/R mice (ADAR2 knockout [KO]) were subjected to feeding with standard chow or high-fat diet (HFD) for 20weeks at the age of 5weeks. The metabolic parameters, hepatic lipid droplet, grip strength test, rotarod test, muscle weight, fibre cross-sectional area (CSA), fibre types and protein associated with protein degradation were examined. Systemic and local tissues serum amyloid A1 (SAA1) were measured. The effects of SAA1 on C2C12 myotube atrophy were investigated. ADAR2 KO mice fed with HFD exhibited lower body weight (-7.7%, P<0.05), lower liver tissue weight (-20%, P<0.05), reduced liver lipid droplets in concert with a decrease in hepatic triglyceride content (-24%, P<0.001) and liver injury (P<0.01). ADAR2 KO mice displayed protection against HFD-induced glucose intolerance, insulin resistance and dyslipidaemia. Skeletal muscle mass (P<0.01), muscle strength (P<0.05), muscle endurance (P<0.001) and fibre size (CSA; P<0.0001) were improved in ADAR2 KO mice fed with HFD compared with WT mice fed with HFD. Muscle atrophy-associated transcripts, such as forkhead box protein O1, muscle atrophy F-box/atrogin-1 and muscle RING finger 1/tripartite motif-containing 63, were decreased in ADAR2 KO mice fed with HFD compared with WT mice fed with HFD. ADAR2 deficiency attenuates HFD-induced local liver and skeletal muscle tissue inflammation. ADAR2 deficiency abolished HFD-induced systemic (P<0.01), hepatic (P<0.0001) and muscular (P<0.001) SAA1 levels. C2C12 myotubes treated with recombinant SAA1 displayed a decrease in myotube length (-37%, P<0.001), diameter (-20%, P<0.01), number (-39%, P<0.001) and fusion index (-46%, P<0.01). Myogenic markers (myosin heavy chain and myogenin) were decreased in SAA1-treated myoblast C2C12 cells. These results provide novel evidence that ADAR2 deficiency may be important in obesity-associated sarcopenia and NAFLD. Increased SAA1 might be involved as a regulatory factor in developing sarcopenia in NAFLD.

Normothermic liver machine perfusion as a dynamic platform for regenerative purposes: What does the future have in store for us?

Liver transplantation has become an immense success; nevertheless, far more recipients are registered on waiting lists than there are available donor livers for transplantation. High-risk, extended criteria donor livers are increasingly used to reduce the discrepancy between organ demand and supply. Especially for high-risk livers, dynamic preservation using machine perfusion can decrease post-transplantation complications and may increase donor liver utilisation by improving graft quality and enabling viability testing before transplantation. To further increase the availability of donor livers suitable for transplantation, new strategies are required that make it possible to use organs that are initially too damaged to be transplanted. With the current progress in experimental liver transplantation research, (long-term) normothermic machine perfusion may be used in the future as a dynamic platform for regenerative medicine approaches, enabling repair and regeneration of injured donor livers. Currently explored therapeutics such as defatting cocktails, RNA interference, senolytics, and stem cell therapy may assist in the repair and/or regeneration of injured livers before transplantation. This review will provide a forecast of the future utility of normothermic machine perfusion in decreasing the imbalance between donor liver demand and supply by enabling the repair and regeneration of damaged donor livers.

990-P: Therapeutic Effect of a Novel Long-Acting GLP-1/GIP/Glucagon Triple Agonist (HM15211) in a NASH and Fibrosis Animal Model

NASH, a severe form of NAFLD, can lead to end stage liver disease such as cirrhosis. Despite increasing prevalence and as a burden for public health, advances in the development of therapeutics are slow with yet no approved drug for NASH treatment. Since liver fat accumulation and inflammation are associated with NASH progression, targeting both aspects may contribute to NASH resolution and fibrosis improvement. Thus, to directly aid those aspects, we developed a novel long-acting, GLP-1/GIP/Glucagon triple agonist, HM15211. With a unique activity profile, HM15211 showed a liver preferential distribution, and exerted potent hepatic triglyceride (TG) reduction in addition to efficient weight loss in DIO mice, suggesting HM15211 as a novel therapeutic option for NASH treatment. Here, we evaluated the therapeutic potential of HM15211 in NASH and fibrosis animal models including monkeys. In MCD-diet mice (6 weeks induction), HM15211 led to significant decrease in hepatic TG content (-82.6% vs. vehicle), which coincided with reduction of elevated ALT and bilirubin. Time course MRI confirmed the progressive resolution of steatosis. Histological analysis also indicated a significant reduction both in hepatic inflammatory gene expression and NAFLD activity score (1.3 for HM15211, 3.4 for liraglutide, and 2.7 for vehicle). To further evaluate the therapeutic potential in fibrosis, MCD-diet mice were used for an extended period (up to 12 weeks induction) for overt liver fibrosis induction. In line with NASH improvement, HM15211 reduced hepatic hydroxyproline and the fibrosis score markedly. Finally, obese and NASH monkeys were administered with HM15211, and efficient weight loss, improvement of lipotoxicity and improvement of histological NASH/fibrosis markers were confirmed in primates too. Based on these results, HM15211 may provide efficacy for the treatment of NASH and fibrosis. Further studies are needed to assess the clinical relevance of these findings. Disclosure J. Kim: None. J. Lee: None. D. Kim: None. E. Park: None. Y. Kim: None. I. Choi: Employee; Self; Hanmi Pharm. Co., Ltd.

Leptin Activates Hepatic 5′-AMP-activated Protein Kinase through Sympathetic Nervous System and α1-Adrenergic Receptor: A POTENTIAL MECHANISM FOR IMPROVEMENT OF FATTY LIVER IN LIPODYSTROPHY BY LEPTIN

AMPK activation promotes glucose and lipid metabolism. Hepatic AMPK activities were decreased in fatty liver from lipodystrophic mice, and leptin activated the hepatic AMPK via the α-adrenergic effect. Leptin improved the fatty liver possibly by activating hepatic AMPK through the central and sympathetic nervous systems. Hepatic AMPK plays significant roles in the pathophysiology of lipodystrophy and metabolic action of leptin. Leptin is an adipocyte-derived hormone that regulates energy homeostasis. Leptin treatment strikingly ameliorates metabolic disorders of lipodystrophy, which exhibits ectopic fat accumulation and severe insulin-resistant diabetes due to a paucity of adipose tissue. Although leptin is shown to activate 5'-AMP-activated protein kinase (AMPK) in the skeletal muscle, the effect of leptin in the liver is still unclear. We investigated the effect of leptin on hepatic AMPK and its pathophysiological relevance in A-ZIP/F-1 mice, a model of generalized lipodystrophy. Here, we demonstrated that leptin activates hepatic AMPK through the central nervous system and α-adrenergic sympathetic nerves. AMPK activities were decreased in the fatty liver of A-ZIP/F-1 mice, and leptin administration increased AMPK activities in the liver as well as in skeletal muscle with significant reduction in triglyceride content. Activation of hepatic AMPK with A769662 also led to a decrease in hepatic triglyceride content and blood glucose levels in A-ZIP/F-1 mice. These results indicate that the down-regulation of hepatic AMPK activities plays a pathophysiological role in the metabolic disturbances of lipodystrophy, and the hepatic AMPK activation is involved in the therapeutic effects of leptin.

VO(dmpp)2 normalizes pre-diabetic parameters as assessed by in vivo magnetic resonance imaging and spectroscopy

Type 2 diabetes mellitus has been associated with obesity, metabolic syndrome, cardiovascular diseases and cancer. Attempts have been made for early diagnosis and finding effective drugs to prevent severe consequences and ameliorate the symptoms of this disorder. In this work, the pharmacological properties of VO(dmpp)2, [bis(1,2-dimethyl-3-hydroxy-4-pyridinonato)oxovanadium(IV)], were in vivo evaluated. For 4weeks fatty Zucker rats were subjected to a daily dose of VO(dmpp)2 (44μmol/kg) and their metabolic profile was followed by assessing different biological parameters at established time points: body weight, subcutaneous fat width and hepatic triglyceride content determined by magnetic resonance imaging and spectroscopy, respectively. A glucose tolerance test was performed at the end of the experiment. After treatment, treated obese rats presented a weight significantly lower than the non-treated obese animals (359.0±11.1 vs. 433.5±6.2g, P<0.05), a thinner subcutaneous fat width, and a statistically significant decrease in hepatic triglyceride content (5.41±0.59 vs. 21.03±1.40%, P<0.0005). Additionally, the glucose intolerant profile of fatty Zucker rats was completely reversed in treated animals (102.3±2.1 vs. 172.4±1.3mg/100mL; P<0.0005). These results reinforce the therapeutic action of VO(dmpp)2 which shows particular effects on lipid metabolism.

Prolonged Caloric Restriction in Obese Patients With Type 2 Diabetes Mellitus Decreases Plasma CETP and Increases Apolipoprotein AI Levels Without Improving the Cholesterol Efflux Properties of HDL

OBJECTIVEUsing a mouse model for human-like lipoprotein metabolism, we observed previously that reduction of the hepatic triglyceride (TG) content resulted in a decrease in plasma cholesteryl ester transfer protein (CETP) and an increase in HDL levels. The aim of the current study was to investigate the effects of prolonged caloric restriction in obese patients with type 2 diabetes mellitus, resulting in a major reduction in hepatic TG content, on plasma CETP and HDL levels.RESEARCH DESIGN AND METHODSWe studied 27 obese (BMI: 37.2 ± 0.9 kg/m2) insulin-dependent patients with type 2 diabetes mellitus (14 men and 13 women, aged 55 ± 2 years) who received a 16-week very low calorie diet (VLCD). At baseline and after a 16-week VLCD, plasma lipids, lipoproteins, and CETP were measured. Furthermore, functionality of HDL with respect to inducing cholesterol efflux from human monocyte cells (THP-1) was determined.RESULTSA 16-week VLCD markedly decreased plasma CETP concentration (−18%; P < 0.01) and increased plasma apolipoprotein (apo)AI levels (+16%; P < 0.05), without significantly affecting plasma HDL-cholesterol and HDL-phospholipids. Although a VLCD results in HDL that is less lipidated, the functionality of HDL with respect to inducing cholesterol efflux in vitro was unchanged.CONCLUSIONSThe marked decrease in hepatic TG content induced by a 16-week VLCD is accompanied by a decrease in plasma CETP concentration and an increase in apoAI levels, without improving the cholesterol efflux properties of HDL in vitro.

Constitutive Androstane Receptor Activation Decreases Plasma Apolipoprotein B–Containing Lipoproteins and Atherosclerosis in Low-Density Lipoprotein Receptor–Deficient Mice

The goal of this study was to determine the impact of the nuclear receptor constitutive androstane receptor (CAR) on lipoprotein metabolism and atherosclerosis in hyperlipidemic mice. Low-density lipoprotein receptor-deficient (Ldlr(-/-)) and apolipoprotein E-deficient (ApoE(-/-)) mice fed a Western-type diet were treated weekly with the Car agonist 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) or the vehicle only for 8 weeks. In Ldlr(-/-) mice, treatment with TCPOBOP induced a decrease in plasma triglyceride and intermediate-density lipoprotein/low-density lipoprotein cholesterol levels (≈30% decrease in both cases after 2 months, P<0.01). These mice also showed a significant reduction in the production of very-low-density lipoproteins associated with a decrease in hepatic triglyceride content and the repression of several genes involved in lipogenesis. TCPOBOP treatment also induced a marked increase in the very-low-density lipoprotein receptor in the liver, which probably contributed to the decrease in intermediate-density lipoprotein/low-density lipoprotein levels. Atherosclerotic lesions in the aortic valves of TCPOBOP-treated Ldlr(-/-) mice were also reduced (-60%, P<0.001). In ApoE(-/-) mice, which lack the physiological apoE ligand for the very-low-density lipoprotein receptor, the effect of TCPOBOP on plasma cholesterol levels and the development of atherosclerotic lesions was markedly attenuated. CAR is a potential target in the prevention and treatment of hypercholesterolemia and atherosclerosis.

Pioglitazone Decreases Plasma Cholesteryl Ester Transfer Protein Mass, Associated With a Decrease in Hepatic Triglyceride Content, in Patients With Type 2 Diabetes

OBJECTIVEThiazolidinediones reduce hepatic steatosis and increase HDL cholesterol levels. In mice with human-like lipoprotein metabolism (APOE*3-Leiden.CETP transgenic mice), a decrease in hepatic triglyceride content is associated with a decrease in plasma cholesteryl ester transfer protein (CETP) mass and an increase in HDL levels. Therefore, the aim of the present study was to assess the effects of pioglitazone on CETP mass in patients with type 2 diabetes.RESEARCH DESIGN AND METHODSWe included 78 men with type 2 diabetes (aged 56.5 ± 0.6 years; HbA1c 7.1 ± 0.1%) who were randomly assigned to treatment with pioglitazone (30 mg/day) or metformin (2000 mg/day) and matching placebo, in addition to glimepiride. At baseline and after 24 weeks of treatment plasma HDL cholesterol levels and CETP mass were measured, and hepatic triglyceride content was assessed by proton magnetic resonance spectroscopy.RESULTSPioglitazone decreased hepatic triglyceride content (5.9 [interquartile range 2.6–17.4] versus 4.1 [1.9–12.3]%, P < 0.05), decreased plasma CETP mass (2.33 ± 0.10 vs. 2.06 ± 0.10 μg/ml, P < 0.05), and increased plasma HDL cholesterol level (1.22 ± 0.05 vs. 1.34 ± 0.05 mmol/l, P < 0.05). Metformin did not significantly change any of these parameters.CONCLUSIONSA decrease in hepatic triglyceride content by pioglitazone is accompanied by a decrease in plasma CETP mass and associated with an increase in HDL cholesterol levels. These results in patients with type 2 diabetes fully confirm recent findings in mice.

BENEFICIAL EFFECT OF XANTHOANGELOL, A CHALCONE COMPOUND FROM ANGELICA KEISKEI, ON LIPID METABOLISM IN STROKE‐PRONE SPONTANEOUSLY HYPERTENSIVE RATS

1. Recently, we reported that 4-hydroxyderricin, one of the major chalcones in Angelica keiskei extract (ethyl acetate extract from the yellow liquid of stems), exerted hypotensive and lipid regulatory actions in stroke-prone spontaneously hypertensive rats (SHRSP). In the present study, we isolated xanthoangelol, another major chalcone in A. keiskei extract, and examined the effect of dietary xanthoangelol on blood pressure and lipid metabolism in SHRSP. 2. Six-week-old male SHRSP were fed diets containing 0.02% or 0.1% xanthoangelol (0.02 and 0.10 Xan, respectively) for 7 weeks, with free access to the diet and water. There were no significant changes in daily food intake, bodyweight or systolic blood pressure throughout the experimental period. Serum total cholesterol levels tended to decrease in the two experimental groups (albeit not significantly), which was due to a dose-dependent decrease in the cholesterol content of the low-density lipoprotein (LDL) fraction. These results suggest that dietary xanthoangelol decreases serum LDL levels. 3. In the liver, significant dose-dependent decreases in relative liver liver weight and total triglyceride content were seen in the 0.02 and 0.10 Xan groups. In addition, a significant decrease in total cholesterol content was found in the 0.10 Xan group, which may be due to an elevation of faecal cholesterol excretion in addition to the decrease in liver weight. 4. Investigation of the hepatic mRNA expression of proteins involved in lipid metabolism indicated that there was a significant increase in peroxisome proliferator-activated receptor (PPAR) alpha mRNA expression associated with the tendency for increases in acyl-coenzyme A (CoA) synthetase and acyl-CoA oxidase mRNA expression in the 0.10 Xan group, which may be responsible, at least in part, for the decrease in hepatic triglyceride content in the xanthoangelol-treated rats. In addition, a significant increase in LDL receptor mRNA expression in the 0.10 Xan group may be responsible, at least in part, for the decrease in serum LDL levels in the xanthoangelol-treated rats. 5. In conclusion, dietary xanthoangelol results in a reduction of serum LDL levels and decreases in total cholesterol and triglyceride contents in the liver of SHRSP. These beneficial effects are more effective following consumption of diet containing 0.10% xanthoangelol.

Beneficial effect of laserpitin, a coumarin compound from Angelica keiskei, on lipid metabolism in stroke‐prone spontaneously hypertensive rats

Recently, we found that 4-hydroxyderricin, one of the major chalcones in Angelica keiskei extract (an ethyl acetate extract from the yellow liquid of stems), suppressed increases in systolic blood pressure and reduced both serum very low-density lipoprotein levels and liver triglyceride content in stroke-prone spontaneously hypertensive rats (SHRSP). In the present study, we have isolated laserpitin, a characteristic coumarin, from the A. keiskei extract and examined the effect of dietary laserpitin on blood pressure and lipid metabolism in SHRSP. Six-week-old male SHRSP were fed diets containing 0.1% laserpitin for 7 weeks with free access to the diet and water. Bodyweight gain was reduced by dietary laserpitin after 4 weeks through to 7 weeks without any significant change in daily food intake. Serum total cholesterol, phospholipid and apolipoprotein (apo) E levels were significantly increased, which was due to significant increases in cholesterol, phospholipid and apoE contents in the low- and high-density lipoprotein (LDL and HDL, respectively) fractions. These results suggest that dietary laserpitin increases serum apoE-HDL levels. In the liver, significant decreases in relative liver weight and triglyceride content were found after treatment with laserpitin for 7 weeks. An investigation of hepatic mRNA expression of proteins involved in lipid metabolism indicated that a significant decrease in hepatic triglyceride lipase may be responsible for the increase in serum HDL levels and also indicated that a marked decrease in adipocyte determination and differentiation factor 1 may be responsible, at least in part, for the decrease in hepatic triglyceride content. In conclusion, dietary laserpitin produces increases in serum HDL levels, especially apoE-HDL, and decreases in the hepatic triglyceride content in SHRSP.

Hypotensive and lipid regulatory actions of 4‐hydroxyderricin, a chalcone from Angelica keiskei, in stroke‐prone spontaneously hypertensive rats

1. Previously, we found that Angelica keiskei extract (ethyl acetate extract from the yellow liquid of stems) elevated serum high-density lipoprotein (HDL) levels and reduced liver triglyceride content in stroke-prone spontaneously hypertensive rats (SHRSP). To identify the active substance in A. keiskei extract, we examined the effect of 4-hydroxyderricin, a characteristic chalcone isolated from the yellow liquid of stems, on blood pressure and lipid metabolism in SHRSP. 2. Six-week-old male SHRSP were fed diets containing 0.07% 4-hydroxyderricin for 7 weeks with free access to the diet and water. Elevation of systolic blood pressure was significantly suppressed after 7 weeks treatment. Serum very low-density lipoprotein (VLDL) levels were significantly reduced, without any effect on HDL levels, and were associated with a significant decrease in the serum concentration of free fatty acids. 3. In the liver, significant decreases in relative liver weight and triglyceride content were found after treatment with 4-hydroxyderricin for 7 weeks. 4. An investigation of hepatic mRNA expression of proteins involved in lipid metabolism indicated that a significant decrease in microsomal triglyceride transferprotein may be responsible for the decrease in serum VLDL levels and that significant decreases in adipocyte determination and differentiation factor 1 and fatty acid synthase may be responsible for the decrease in hepatic triglyceride content. 5. In conclusion, dietary 4-hydroxyderricin produces suppression of the elevation of systolic blood pressure, reduction of serum VLDL levels and a decrease in hepatic triglyceride content in SHRSP.

Induction of fatty liver by fasting in suncus.

We found that a fatty liver was easily induced in a novel experimental animal, Suncus murinus (suncus), by withholding food. Hepatic triglyceride content increased linearly for up to 24 h after fasting in these animals. Serum levels of neutral lipids are very low in the fed state compared with those in rats, and decreased significantly after 24 h fasting. On the other hand, serum free fatty acids, which are at the same level in fed animals as in rats, increased threefold in the fasting suncus. In order to learn whether the fatty liver induced by fasting is an unusual physiological state or a pathological on-going state in suncus, they were refed after 24 h fasting. Refeeding resulted in a decrease in hepatic triglyceride content to the level of fed animals. Serum lipid levels, which decreased with fasting, returned to those of fed animals. This evidence indicates that hepatic lipid secretion is impaired even in a physiological state to some extent and that starvation causes increasing influx of free fatty acid to the liver, which might be followed by esterification and result in triglyceride accumulation in the liver. In conclusion, hepatic lipid and lipoprotein metabolism is unique to the suncus, which is a useful animal model for the study of intra-hepatic lipid transport.

Diurnal Changes in Plasma and Liver Lipids and Lipoprotein Lipase Activity in Heart and Adipose Tissue in Rats Fed a High and Low Fat Diet

In order to evaluate a) the respective roles of adipose and muscle lipoprotein lipase (LPL) in the clearing of alimentary lipemia and b) the role of the resulting nonesterified fatty acids (NEFA) in controlling hepatic ketogenesis and liver triglyceride content, a number of parameters related to lipid metabolism were studied over the 24 hour period (the dark period being from 1930 to 0730 hours), in rats ad libitum fed either a low-fat (LF) or a high-fat (HF) diet containing respectively 1.1% and 41.5% lard. During spontaneous feeding (from 1500-1800 hours onwards), LPL activity in LF rats increased in adipose tissue and decreased in heart; in rats fed the HF diet for 3 weeks, the postprandial rise in adipose LPL was smaller and there was no decrease in heart LPL before 2100 hours. In HF rats, unlike the LF, feeding resulted in a large increase in circulating NEFA and total ketone concentrations, an increase in liver beta-hydroxybutyrate dehydrogenase activity, and a decrease in hepatic triglyceride content. The findings clearly indicate that in HF rats, muscle LPL controls the postprandial rise in plasma NEFA concentrations, which in turn appear to determine the extent of ketonemia and liver triglyceride changes. The possible control of these metabolic events by insulin is discussed.