• Nutrition Research and Practice
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• v.13 no.5
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• pp.377-383
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• 2019

BACKGROUND/OBJECTIVES: Hyperglycemia-induced hepatic damage has been recognized as one of the major cause of complications in diabetes. Hepatic complications are associated with inflammation and oxidative stress in diabetes. In this study, we investigated the hypothesis that gamma-tocopherol (GT) supplementation ameliorates NLRP3 inflammasome associated hepatic inflammation in diabetes. MATERIALS/METHODS: Diabetes was induced by the intraperitoneal injection of alloxan (150 mg/kg. BW) in ICR mice. All mice were fed with a control diet (AIN-76A). After diabetes was induced (fasting glucose level ${\geq}250mg/dL$), the mice were treated with tocopherol-stripped corn oil or GT-supplemented (35 mg/kg) corn oil, respectively, by gavage for 2 weeks. RESULTS: GT supplementation reduced fasting blood glucose levels in diabetic mice relative to non-treated diabetic mice. Moreover, GT supplementation ameliorated hyperglycemia-induced hepatic damage by regulation of NOD-like receptor protein 3 (NLRP3)-inflammasome associated inflammation represented by NLRP3, apoptosis-associated speck-like protein containing a caspase-recruitment domain, caspase-1, nuclear $factor-{\kappa}B$ pathway as well as oxidative stress demonstrated by nuclear factor erythroid 2-related factor 2, NAD(P)H dehydrogenase quinone 1, catalase and glutathione-dependent peroxidase in diabetic mice. CONCLUSION: The findings suggested that GT supplementation ameliorated hepatic damage by attenuating inflammation and oxidative stress in alloxan-induced diabetic mice. Taken together, GT could be a beneficial nutrient that can ameliorate inflammatory responses associated with NLRP3 inflammasome in hyperglycemia-induced hepatic damage.

• Biomedical Science Letters
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• v.23 no.2
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• pp.144-153
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• 2017

It was demonstrated that Gangjihwan (DF), which is the herbal composition composed of Ephedra intermedia, Lithospermum erythrorhizon, and Rheum palmatum, inhibits obesity and hepatic steatosis in high fat diet (HFD)-fed obese mice. The aim of this study was to determine the effects of DF on visceral obesity, hepatic inflammation and fibrosis and the mechanism of actions involved in this process using in vivo and in vitro approaches. DF was extracted with water (DF-FW), 30% grain alcohol (DF-GA30), and 70% grain alcohol (DF-GA70). Administration of DF to HFD-fed control mice decreased visceral tissue mass and visceral adipocyte size without adverse effects. Visceral fat mass was decreased by DF-GA30 and DF-GA70, and visceral adipocyte size by all three DF extracts compared with obese control mice. Histological analysis revealed that three kinds of DF extracts reduced toluidine blue-stained mast cells and collagen accumulation in the liver, the extents of which were most eminent in DF-GA70-treated mice. DF-GA70 decreased the mRNA levels of the inflammation ($TNF{\alpha}$ and VCAM-1), fibrosis (${\alpha}-SMA$), and apoptosis (caspase 3) genes, but increasing the anti-apoptosis gene (Bcl-2) mRNA levels in the liver of obese control mice. Consistent with the in vivo data, GA-70 also altered the expression of inflammation genes ($TNF{\alpha}$ and MCP-1) in HepG2 cells. These results indicate that DF not only inhibits visceral obesity, but also ameliorates visceral obesity-induced hepatic inflammation and fibrosis and that this process may be mediated by regulating the hepatic expression of inflammatory and fibrogenic genes.

• Toxicological Research
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• v.22 no.3
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• pp.267-273
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• 2006

Tungtungmadic acid(3-caffeoyl, 4-dihydrocaffeoyl quinic acid: CDCQ) is a new chlorogenic acid derivative isolated from the Salicornia herbacea. The suppressive effects of CDCQ on the progress of acute carbon tetrachloride($CCl_4$)-induced hepatic fibrosis were investigated in mice. CDCQ significantly suppressed $CCl_4$-induced hepatic necrosis and inflammation, as determined by serum enzymatic activities of alanine and aspartate aminotransferase and serum TNF-$\alpha$ levels in a dose-dependent manner. In addition, increased hepatic lipid peroxidation and fibrosis after acute $CCl_4$ treatment were suppressed by the administration of CDCQ. CDCQ also significantly prevented the elevation of hepatic hydroxyproline and collagen content and ${\alpha}$-smooth muscle actin(${\alpha}$-SMA) expression in the liver of $CCl_4$-intoxicated mice. These results suggest that the suppressive effects of CDCQ against the acute $CCl_4$-induced hepatic fibrosis possibly related to its ability to block both hepatic inflammation and the activation of hepatic stellate cells.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.114-114
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• 2022

Excessive endogenous endotoxin, especially lipopolysaccharide (LPS) reflux from gastrointestinal (GI) tract to the liver tissue is one of the most serious reasons of severe and acute liver injury which is mainly mediated by Kupffer cell activations. However, there is no clear molecular clues to explain the exact pathophysiological mechanism and effective drugs available till nowadays. We aimed to comprehend the pathophysiological features of LPS-induced liver injury and evaluate the efficacies of potential therapeutic drug, Ga-mi-Yuk-Mi-Jihwang-Tang (GYM), which is composed of herbal plants. GYM remarkably caused to normalize hepatic inflammation and oxidations against LPS-induced liver injury by evidence of serum liver enzymes, histopathological analysis, both hepatic protein and gene expression levels of pro-inflammatory cytokines, nitric oxide levels, and hepatic tissue levels of reactive oxygen species (ROS) levels, malondialdehyde (MDA), and 4-hydroxyneoneal, respectively. To assess molecular events in the hepatic tissue, we further found hepatic Sirtuin6 (Sirt6) levels were considerably depleted by LPS injection with aberrant alterations of Nrf2/HO-1 signaling pathways, whereas administration with GYM notably exerted to normalize these abnormalities. Our results exhibited that GYM would be one of target drug to diminish hepatic inflammation as well as oxidative stress by regulation of hepatic Sirt6 levels.

• BMB Reports
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• v.55 no.4
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• pp.166-174
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• 2022

Hepatic macrophages are key immune cells associated with the broad ranges of liver diseases including steatosis, inflammation and fibrosis. Hepatic macrophages interact with other immune cells and orchestrate hepatic immune circumstances. Recently, the heterogenous populations of hepatic macrophages have been discovered termed residential Kupffer cells and monocyte-derived macrophages, and identified their distinct population dynamics during the progression of various liver diseases. Liver injury lead to Kupffer cells activation with induction of inflammatory cytokines and chemokines, which triggers recruitment of inflammatory monocyte-derived macrophages. To understand liver pathology, the functions of different subtypes of liver macrophages should be regarded with different perspectives. In this review, we summarize recent advances in the roles of hepatic macrophages under liver damages and suggest hepatic macrophages as promising therapeutic targets for treating liver diseases.

• Biomedical Science Letters
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• v.28 no.2
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• pp.101-108
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• 2022

High-fat diet (HFD)-fed ovariectomized (OVX) female mice were used as an animal model of obese postmenopausal women. We investigated the effects of ascorbic acid on the histological changes induced in the liver. Plasma alanine aminotransferase levels and liver weights were higher in mice fed an HFD for 18 weeks than in mice fed a low-fat diet, effects that were inhibited by ascorbic acid. Similarly, mice fed an ascorbic acid-supplemented HFD had less hepatic lipid accumulation than did mice fed an HFD alone. Moreover, administration of ascorbic acid reduced inflammatory cells, including mast cells and CD68-positive cells, and inflammatory foci in the liver and inhibited hepatocyte ballooning. Hepatic collagen levels were lower in ascorbic acid-treated versus non-treated mice. These results suggest that ascorbic acid inhibits hepatic steatosis, inflammation, and fibrosis in obese OVX mice. Thus, ascorbic acid intake may be useful for postmenopausal women with nonalcoholic fatty liver disease.

• The Korea Journal of Herbology
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• v.37 no.5
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• pp.17-26
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• 2022

Objective : The aim of the present study is to examine hepatic lipid-lowering and anti-inflammatory effects of silymarin combined with Jakyakgamcho-tang on non-alcoholic fatty liver disease in a high fat diet-induced obese mice model. Methods : C57BL/6 mice were divided into four dietary groups: (1) Normal, (2) Control (60% high-fat diet), (3) Control + silymarin 50 mg/kg/day (Silymarin), (4) Control + Silymarin 50 mg/kg/day + Jakyakgamcho-tang 100 mg/kg/day (SPG). After 12 weeks administration, mice were sacrificed and lipids and inflammation-related biomarkers were analyzed liver and plasma. Results : Silymarin and SPG treatments significantly lowered body and liver weights compared to the Control. Serumlipids (triglyceride (TG), total cholesterol) and pro-inflammatory cytokines (tumor necrosis factor alpha, interleukin 1𝛽, and IL-6) concentrations were significantly lowered in the Silymarin and SPG groups than the Control group. Silymarin and SPG treatments suppressed hepatic TG level and hepatic lipid droplets compared to the Control. Theses two treatments significantly increased hepatic kinase B1 and AMP-activated protein kinase protein levels, and significantly decreased hepatic key lipogenic enzymes (acetyl-CoA carboxylase, fatty acid synthase and stearyl coenzyme A desaturase 1) protein levels than the Control. SPG also significantly increased hepatic fatty acid oxidation-related protein (peroxisome proliferator-activated receptor alpha and uncoupling protein 2) levels than the Control. Conclusions: Silymarin and SPG suppressed hepatic lipid accumulation by regulating hepatic protein expression, and lowered blood pro-inflammatory cytokines concentrations though the synergic effect of silymarin and Jakyakgamchotang was not clear.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.5
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• pp.451-460
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• 2015

Sirtuin 1 (SIRT1) is a mammalian $NAD^+$-dependent protein deacetylase that regulates cellular metabolism and inflammatory response. The organ-specific deletion of SIRT1 induces local inflammation and insulin resistance in dietary and genetic obesity. Macrophage-mediated inflammation contributes to insulin resistance and metabolic syndrome, however, the macrophage-specific SIRT1 function in the context of obesity is largely unknown. C57/BL6 wild type (WT) or myeloid-specific SIRT1 knockout (KO) mice were fed a high-fat diet (HFD) or normal diet (ND) for 12 weeks. Metabolic parameters and markers of hepatic steatosis and inflammation in liver were compared in WT and KO mice. SIRT1 deletion enhanced HFD-induced changes on body and liver weight gain, and increased glucose and insulin resistance. In liver, SIRT1 deletion increased the acetylation, and enhanced HFD-induced nuclear translocation of nuclear factor kappa B (NF-${\kappa}B$), hepatic inflammation and macrophage infiltration. HFD-fed KO mice showed severe hepatic steatosis by activating lipogenic pathway through sterol regulatory element-binding protein 1 (SREBP-1), and hepatic fibrogenesis, as indicated by induction of connective tissue growth factor (CTGF), alpha-smooth muscle actin (${\alpha}$-SMA), and collagen secretion. Myeloid-specific deletion of SIRT1 stimulates obesity-induced inflammation and increases the risk of hepatic fibrosis. Targeted induction of macrophage SIRT1 may be a good therapy for alleviating inflammation-associated metabolic syndrome.

• Clinical Nutrition Research
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• v.12 no.2
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• pp.154-167
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• 2023

Hepatic encephalopathy (HE) associated with liver failure is accompanied by hyperammonemia, severe inflammation, depression, anxiety, and memory deficits as well as liver injury. Recent studies have focused on the liver-brain-inflammation axis to identify a therapeutic solution for patients with HE. Lipocalin-2 is an inflammation-related glycoprotein that is secreted by various organs and is involved in cellular mechanisms including iron homeostasis, glucose metabolism, cell death, neurite outgrowth, and neurogenesis. In this study, we investigated that the roles of lipocalin-2 both in the brain cortex of mice with HE and in Neuro-2a (N2A) cells. We detected elevated levels of lipocalin-2 both in the plasma and liver in a bile duct ligation mouse model of HE. We confirmed changes in cytokine expression, such as interleukin-1β, cyclooxygenase 2 expression, and iron metabolism related to gene expression through AKT-mediated signaling both in the brain cortex of mice with HE and N2A cells. Our data showed negative effects of hepatic lipocalin-2 on cell survival, iron homeostasis, and neurite outgrowth in N2A cells. Thus, we suggest that regulation of lipocalin-2 in the brain in HE may be a critical therapeutic approach to alleviate neuropathological problems focused on the liver-brain axis.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.6
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• pp.459-466
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• 2019

Dipeptidyl peptidase (DPP)-4 inhibitors, or gliptins, are a class of oral hypoglycemic drugs that have been widely used as a second-line treatment for type 2 diabetes. Gliptins, which were introduced for clinical use a decade ago, have been shown to be beneficial against nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NASH) in animals and humans. Cenicriviroc (CVC), a dual antagonist of C-C chemokine receptor type 2 and 5, is currently under investigation against NASH and fibrosis. It was previously discovered that evogliptin (EVO) reduces hepatic steatosis in diet-induced obese animals but the effectiveness of EVO on NASH remains unexplored. Here, we compared the effectiveness of EVO and CVC against NASH and fibrosis in mice fed a high-fat and high-fructose diet (HFHF). Biochemical and histological analyses showed that mice fed a HFHF for 20 weeks developed severe hepatic steatosis and inflammation with mild fibrosis. Administration of EVO (0.2% wt/wt) for the last 8 weeks of HFHF feeding significantly reduced hepatic triglyceride accumulation, inflammation, and fibrosis as well as restored insulin sensitivity, as evidenced by lowered plasma insulin levels and the improvement in insulin tolerance test curves. Treatment of mice with CVC (0.1% wt/wt) inhibited hepatic inflammation and fibrogenesis with similar efficacy to that of EVO, without affecting hepatic steatosis. CVC treatment also reduced plasma insulin concentrations, despite no improvement in insulin tolerance. In conclusion, EVO administration efficiently ameliorated the development of NASH and fibrosis in HFHF-fed mice, corroborating its therapeutic potential.