scholarly journals Sequestration of Vitamin E by Liver Fat in vivo, in vitro and in Women with Hepato-steatosis

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1696-1696
Author(s):  
Pierre-Christian Violet ◽  
Ifechukwude Ebenuwa ◽  
Stacey Chung ◽  
Jeffrey Atkinson ◽  
Danny Manor ◽  
...  

Abstract Objectives Hepato-steatosis (HS) due to obesity is now the most common cause of chronic liver disease in the Americas and Western Europe. The only means to prevent disease is avoidance of obesity. α-Tocopherol at doses of 800 I.U. daily was reported to have partial treatment effects for NASH. Because alpha tocopherol is a fat-soluble vitamin, we hypothesized that excess fat in liver, as found in HS, could act unintentionally sequester vitamin E, thereby altering its normal physiology and contributing to development of NASH. Using oral and intravenous deuterated tocopherols, evidence showing HS altered a-tocopherol physiology was reported based on pharmacokinetics studies in obese women with HS. Here we further tested the sequestration hypothesis in vitro, and in vivo. Methods In vitro, we investigated effects of fat on intracellular vitamin E localization. Control human and mouse hepatocytes and hepatocytes pre-loaded with fat were incubated with fluorescent α-tocopherol (BDP-α-tocopherol). In vivo experiments were performed using mice fed a high fat diet with different vitamin E doses. Results Compared to controls, fat- loaded cells contained more a-tocopherol, and BDP-a-tocopherol was specifically localized into intracellular fat droplets. In cells incubated with BDP a-tocopherol, we found that fat loading decreased a-tocopherol release. Induced expression of TPP, which mediates vitamin E intracellular disposition under normal conditions, was not observed in fat loaded cells, further confirming vitamin E was trapped in fat. Livers of mice fed high fat diet had more vitamin E compared to controls. By further increasing vitamin E content of the high fat diet, we observed a reduction in liver size and liver fat in the high vitamin E group. Using a mouse metabolic chamber, we observed a slight reduction of oxygen consumption rate in the high vitamin E group compared to controls. Conclusions Considered together, these findings imply that fat in the liver may produce unrecognized hepatic vitamin E sequestration, which could drive liver disease. These results are consistent with the possibility that increased vitamin E intake might, if begun at an early stage, restore vitamin E physiology, potentially decreasing or preventing progression of HS to NASH. Funding Sources NIH intramural program (DK053213–14).

2020 ◽  
Author(s):  
Ada Admin ◽  
Wenquan Zhang ◽  
Dong Yang ◽  
Yangmian Yuan ◽  
Chong Liu ◽  
...  

Crosstalk among different tissues and organs is a hotspot in metabolic research. Recent studies have revealed the regulatory roles of a number of myokines in metabolism. Here, we report that female mice muscle-specific lacking histone methylase G9a (<i>Ehmt2</i><sup>Ckmm </sup>KO<i> </i>or <i>Ehmt2</i><sup>HSA</sup> KO) are resistant to high-fat-diet (HFD) induced obesity and hepatic steatosis. Furthermore, we identified significantly upregulated circulating level of musclin, a myokine, in HFD-fed <i>Ehmt2</i><sup>Ckmm </sup>KO or <i>Ehmt2</i><sup>HSA</sup> KO female mice. Similarly, upregulated musclin was observed in mice injected with two structurally different inhibitors for G9a methylase activity, BIX01294 and A366. Moreover, injection of recombinant full-length musclin or its functional core domain, inhibited the HFD-induced obesity and hepatic steatosis in wildtype female and male mice. Mechanistically, G9a methylase activity-dependently regulated muscular musclin level by binding to its promoter, also by regulating p-Foxo1/Foxo1 level <i>in vivo</i> and <i>in vitro</i>. Collectively, these data suggested a critical role for G9a in the ‘muscle-liver-fat’ metabolic axis, at least for female mice. Musclin may serve as a potential therapeutic candidate for obesity and associated diseases.


2020 ◽  
Author(s):  
Ada Admin ◽  
Wenquan Zhang ◽  
Dong Yang ◽  
Yangmian Yuan ◽  
Chong Liu ◽  
...  

Crosstalk among different tissues and organs is a hotspot in metabolic research. Recent studies have revealed the regulatory roles of a number of myokines in metabolism. Here, we report that female mice muscle-specific lacking histone methylase G9a (<i>Ehmt2</i><sup>Ckmm </sup>KO<i> </i>or <i>Ehmt2</i><sup>HSA</sup> KO) are resistant to high-fat-diet (HFD) induced obesity and hepatic steatosis. Furthermore, we identified significantly upregulated circulating level of musclin, a myokine, in HFD-fed <i>Ehmt2</i><sup>Ckmm </sup>KO or <i>Ehmt2</i><sup>HSA</sup> KO female mice. Similarly, upregulated musclin was observed in mice injected with two structurally different inhibitors for G9a methylase activity, BIX01294 and A366. Moreover, injection of recombinant full-length musclin or its functional core domain, inhibited the HFD-induced obesity and hepatic steatosis in wildtype female and male mice. Mechanistically, G9a methylase activity-dependently regulated muscular musclin level by binding to its promoter, also by regulating p-Foxo1/Foxo1 level <i>in vivo</i> and <i>in vitro</i>. Collectively, these data suggested a critical role for G9a in the ‘muscle-liver-fat’ metabolic axis, at least for female mice. Musclin may serve as a potential therapeutic candidate for obesity and associated diseases.


2014 ◽  
Vol 92 (5) ◽  
pp. 405-417 ◽  
Author(s):  
Xian-Wei Li ◽  
Yan Liu ◽  
Wei Hao ◽  
Jie-Ren Yang

Sequoyitol decreases blood glucose, improves glucose intolerance, and enhances insulin signaling in ob/ob mice. The aim of this study was to investigate the effects of sequoyitol on diabetic nephropathy in rats with type 2 diabetes mellitus and the mechanism of action. Diabetic rats, induced with a high-fat diet and a low dose of streptozotocin, and were administered sequoyitol (12.5, 25.0, and 50.0 mg·(kg body mass)−1·d−1) for 6 weeks. The levels of fasting blood glucose (FBG), serum insulin, blood urea nitrogen (BUN), and serum creatinine (SCr) were measured. The expression levels of p22phox, p47phox, NF-κB, and TGF-β1 were measured using immunohistochemisty, real-time PCR, and (or) Western blot. The total antioxidative capacity (T-AOC), as well as the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) were also determined. The results showed that sequoyitol significantly decreased FBG, BUN, and SCr levels, and increased the insulin levels in diabetic rats. The level of T-AOC was significantly increased, while ROS and MDA levels and the expression of p22phox, p47phox, NF-κB, and TGF-β1 were decreased with sequoyitol treatment both in vivo and in vitro. These results suggested that sequoyitol ameliorates the progression of diabetic nephropathy in rats, as induced by a high-fat diet and a low dose of streptozotocin, through its glucose-lowering effects, antioxidant activity, and regulation of TGF-β1 expression.


2017 ◽  
Vol 43 (5) ◽  
pp. 1961-1973 ◽  
Author(s):  
Yan Bai ◽  
Zhenli Su ◽  
Hanqi Sun ◽  
Wei Zhao ◽  
Xue Chen ◽  
...  

Background/Aims: High-fat diet (HFD) causes cardiac electrical remodeling and increases the risk of ventricular arrhythmias. Aloe-emodin (AE) is an anthraquinone component isolated from rhubarb and has a similar chemical structure with emodin. The protective effect of emodin against cardiac diseases has been reported in the literature. However, the cardioprotective property of AE is still unknown. The present study investigated the effect of AE on HFD-induced QT prolongation in rats. Methods: Adult male Wistar rats were randomly divided into three groups: control, HFD, and AE-treatment groups. Normal diet was given to rats in the control group, high-fat diet was given to rats in HFD and AE-treatment groups for a total of 10 weeks. First, HFD rats and AE-treatment rats were fed with high-fat diet for 4 weeks to establish the HFD model. Serum total cholesterol and triglyceride levels were measured to validate the HFD model. Afterward, AE-treatment rats were intragastrically administered with 100 mg/kg AE each day for 6 weeks. Electrocardiogram monitoring and whole-cell patch-clamp technique were applied to examine cardiac electrical activity, action potential and inward rectifier K+ current (IK1), respectively. Neonatal rat ventricular myocytes (NRVMs) were subjected to cholesterol and/or AE. Protein expression of Kir2.1 was detected by Western blot and miR-1 level was examined by real-time PCR in vivo and in vitro, respectively. Results: In vivo, AE significantly shortened the QT interval, action potential duration at 90% repolarization (APD90) and resting membrane potential (RMP), which were markedly elongated by HFD. AE increased IK1 current and Kir2.1 protein expression which were reduced in HFD rats. Furthermore, AE significantly inhibited pro-arrhythmic miR-1 in the hearts of HFD rats. In vitro, AE decreased miR-1 expression levels resulting in an increase of Kir2.1 protein levels in cholesterol-enriched NRVMs. Conclusions: AE prevents HFD-induced QT prolongation by repressing miR-1 and upregulating its target Kir2.1. These findings suggest a novel pharmacological role of AE in HFD-induced cardiac electrical remodeling.


2021 ◽  
Author(s):  
sheng Qiu ◽  
Zerong Liang ◽  
Qinan Wu ◽  
Miao Wang ◽  
Mengliu Yang ◽  
...  

Abstract BackgroundNuclear factor erythroid 2-related factor 2 (Nrf2) is reportedly involved in hepatic lipid metabolism, but the results are contradictory and the underlying mechanism thus remains unclear. Herein we focused on elucidating the effects of Nrf2 on hepatic adipogenesis and on determining the possible underlying mechanism. We established a metabolic associated fatty liver disease (MAFLD) model in high fat diet (HFD) fed Nrf2 knockout (Nrf2 KO) mice; further, a cell model of lipid accumulation was established using mouse primary hepatocytes (MPHs) treated with free fatty acids (FAs). Using these models, we investigated the relationship between Nrf2 and autophagy and its role in the development of MAFLD.ResultsWe observed that Nrf2 expression levels were up-regulated in patients with MAFLD and diet-induced obese mice. Nrf2 deficiency led to hepatic lipid accumulation in vivo and in vitro, in addition to, promoting lipogenesis mainly by increasing SREBP-1 activity. Moreover, Nrf2 deficiency attenuated autophagic flux and inhibited the fusion of autophagosomes and lysosomes in vivo and in vitro. Weakened autophagy caused reduced lipolysis in the liver. Importantly, Chromatin immunoprecipitation-qPCR (ChIP-qPCR) and dual-luciferase assay results proved that Nrf2 bound to LAMP1 promoter and regulated its transcriptional activity. We accordingly report that Nrf2-LAMP1 interaction has an indispensable role in Nrf2-regulated hepatosteatosis. ConclusionsThese data collectively confirm that Nrf2 deficiency promotes hepatosteatosis by enhancing SREBP-1 activity and attenuating autophagy. To conclude, our data reveal a novel multi-pathway effect of Nrf2 on lipid metabolism in the liver, and we believe that multi-target intervention of Nrf2 signaling is a promising new strategy for the prevention and treatment of MAFLD.


Author(s):  
Meng Gu ◽  
Chong Liu ◽  
TianYe Yang ◽  
Ming Zhan ◽  
Zhikang Cai ◽  
...  

The role of high-fat diet (HFD) induced gut microbiota alteration and Ghrelin as well as their correlation in benign prostatic hyperplasia (BPH) were explored in our study. The gut microbiota was analyzed by 16s rRNA sequencing. Ghrelin levels in serum, along with Ghrelin and Ghrelin receptor in prostate tissue of mice and patients with BPH were measured. The effect of Ghrelin on cell proliferation, apoptosis, and induction of BPH in mice was explored. Our results indicated that BPH mice have the highest ratio of Firmicutes and Bacteroidetes induced by HFD, as well as Ghrelin level in serum and prostate tissue was significantly increased compared with control. Elevated Ghrelin content in the serum and prostate tissue of BPH patients was also observed. Ghrelin promotes cell proliferation while inhibiting cell apoptosis of prostate cells. The effect of Ghrelin on enlargement of the prostate was found almost equivalent to that of testosterone propionate (TP) which may be attenuated by Ghrelin receptor antagonist YIL-781. Ghrelin could up-regulate Jak2/pJak2/Stat3/pStat3 expression in vitro and in vivo. Our results suggested that Gut microbiota may associate with Ghrelin which plays an important role in activation of Jak2/Stat3 in BPH development. Gut microbiota and Ghrelin might be pathogenic factors for BPH and could be used as a target for mediation.


2020 ◽  
Vol 39 (8) ◽  
pp. 1005-1018 ◽  
Author(s):  
I Cinar ◽  
Z Halici ◽  
B Dincer ◽  
B Sirin ◽  
E Cadirci

The presence of 5-HT7r’s in both human and rat cardiovascular and immune tissues and their contribution to inflammatory conditions prompted us to hypothesize that these receptors contribute in acute myocardial infarction (MI) with underlying chronic endothelial dysfunction. We investigated the role of 5-HT7 receptors on heart tissue that damaged by isoproterenol (ISO)-induced MI in rats with high-fat diet (HFD). In vitro and in vivo effects of 5-HT7r agonist (LP44) and antagonist (SB269970) have been investigated on the H9C2 cell line and rats, respectively. For in vivo analyses, rats were fed with HFD for 8 weeks and after this period ISO-induced MI model has been applied to rat. To investigate the role of 5-HT7r’s, two different doses of LP44 and SB269970 were evaluated and compared with standard hypolipidemic agent, atorvastatin. In vitro studies showed that LP44 has protective and proliferative effects on rat cardiomyocytes. Also in in vivo studies stimulating 5-HT7r’s by LP44 improved blood lipid profile (decreased total cholesterol, low-density lipoprotein-C, and triglyceride, increased high-density lipoprotein), decreased cardiac damage markers (creatine kinase and troponin-I), and corrected inflammatory status (tumor necrosis factor-α, interleukin-6). Our results showed significant improvement in LP44 administered rats in terms of histopathologic analyses. In damaged tissues, 5-HT7 mRNA expression increased and agonist administration decreased this elevation significantly. We determined for the first time that 5-HT7r’s are overexpressed in ISO-induced MI of rats with underlying HFD-induced endothelial dysfunction. Restoration of this overexpression by LP44, a 5-HT7r agonist, ameliorated heart tissue in physiopathologic, enzymatic, and molecular level, showing the cardiac role of these receptors and suggesting them as future potential therapeutic targets.


2019 ◽  
Vol 8 ◽  
Author(s):  
Paola Vitaglione ◽  
Giovanna Mazzone ◽  
Vincenzo Lembo ◽  
Giuseppe D'Argenio ◽  
Antonella Rossi ◽  
...  

AbstractCoffee consumption is inversely associated with the risk of non-alcoholic fatty liver disease (NAFLD). A gap in the literature still exists concerning the intestinal mechanisms that are involved in the protective effect of coffee consumption towards NAFLD. In this study, twenty-four C57BL/6J mice were divided into three groups each receiving a standard diet, a high-fat diet (HFD) or an HFD plus decaffeinated coffee (HFD+COFFEE) for 12 weeks. Coffee supplementation reduced HFD-induced liver macrovesicular steatosis (P < 0·01) and serum cholesterol (P < 0·001), alanine aminotransferase and glucose (P < 0·05). Accordingly, liver PPAR- α (P < 0·05) and acyl-CoA oxidase-1 (P < 0·05) as well as duodenal ATP-binding cassette (ABC) subfamily A1 (ABCA1) and subfamily G1 (ABCG1) (P < 0·05) mRNA expressions increased with coffee consumption. Compared with HFD animals, HFD+COFFEE mice had more undigested lipids in the caecal content and higher free fatty acid receptor-1 mRNA expression in the duodenum and colon. Furthermore, they showed an up-regulation of duodenal and colonic zonulin-1 (P < 0·05), duodenal claudin (P < 0·05) and duodenal peptide YY (P < 0·05) mRNA as well as a higher abundance of Alcaligenaceae in the faeces (P < 0·05). HFD+COFFEE mice had an energy intake comparable with HFD-fed mice but starting from the eighth intervention week they gained significantly less weight over time. Data altogether showed that coffee supplementation prevented HFD-induced NAFLD in mice by reducing hepatic fat deposition and metabolic derangement through modification of pathways underpinning liver fat oxidation, intestinal cholesterol efflux, energy metabolism and gut permeability. The hepatic and metabolic benefits induced by coffee were accompanied by changes in the gut microbiota.


2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Li Zhong ◽  
Jianghan Yuan ◽  
Lu Huang ◽  
Shan Li ◽  
Liang Deng

Background. Receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL) is significant in the activation of inflammation. Runt-related transcription factor 2 (Runx2) promotes the hepatic infiltration of macrophages in nonalcoholic fatty liver disease (NAFLD). We studied how RANKL affects Runx2-triggered macrophage infiltration in NAFLD. Method. 30 male C57BL/6J mice at 4 weeks of age were utilized in this study, 20 mice received a high-fat diet (HFD), and 10 mice received standard rodent chow over 8 months. The histopathologic features of the liver were identified by H&E, Oil red O, and Masson staining. Runx2, RANKL, and F4/80 were analyzed by western blot, real-time PCR, and immunohistochemistry in vivo, respectively. Lentivirus or siRNA was utilized for transwell assay to investigate the role of RANKL in Runx2-induced macrophage migration in vitro. Results. Compared to controls, during NAFLD development, HFD increased Runx2 and RANKL in vivo in NASH (P<0.01). Meanwhile, a correlation between the expression of Runx2 and RANKL (P<0.05) was evident. In addition, the hepatic infiltration of macrophages was increased upon HFD feeding, and analysis showed that the macrophage infiltration was correlated with the expression of Runx2 or RANKL (P<0.05). In vitro, we found that overexpression or deficiency of Runx2 increased or decreased the production of RANKL in mHSCs. Then, transwell assay revealed that RANKL was involved in Runx2-induced macrophage migration. Conclusions. Overall, RANKL is involved in Runx2-triggered macrophage migration during NAFLD pathogenesis, which may provide an underlying therapeutic target for NAFLD.


2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1795-1795
Author(s):  
Chen Du ◽  
Gina Tran ◽  
Victorine Imrhan ◽  
Chandan Prasad ◽  
Parakat Vijayagopal ◽  
...  

Abstract Objectives The purpose of this study was to compare the effects of alpha tocopherol, gamma tocopherol, and the combination of alpha and gamma tocopherols on bone mineral density (BMD), bone mineral content (BMC), and bone metabolism in C57BL/6 J mice fed a high-fat diet. Methods A total of 75 male C57BL/6 mice were randomized to either a low fat diet (LFD) with 6% fat, a high fat diet (HFD) with 20% fat, HFD supplemented with alpha tocopherol (AT), gamma tocopherol (GT), or the combination of AT and GT. LFD and HFD were provided to corresponding groups of mice without vitamin E isoform supplements for 15 weeks to induce bone loss. At the end of the 15 weeks, AT, GT, and a combination of AT and GT were added to 3 of the HFD groups and fed for 10 weeks. LFD group and one of the HFD groups were continued on the same diet for another 10 weeks without additional supplements. All mice were euthanized at the end of the 25 weeks period. Left and right fibula bones were excised, cleaned, and scanned using the Lunar PIXImus dual-energy x-ray absorptiometry (DEXA) densitometer to assess BMD, BMC, lean tissue, and fat tissue content. Serum biomarkers of bone metabolism were evaluated post euthanization. Results HFD resulted in significantly lower fibular BMD and higher tibial bone fat content in comparison to LFD. Animals in the HFD supplemented with GT, but not AT, showed significantly reduced effect of HFD in lowering BMD. Additionally, in the group fed HFD supplemented with GT, a significantly higher concentration of alkaline phosphatase (ALP) and N-terminal propeptide of type I procollagen (PINP) were noted, compared to LFD. This may be indicative of increased bone formation resulting from GT incorporated into the HFD diet. Conclusions The findings of the study suggest that different isoforms of vitamin E affect bone density and bone metabolism differently. Within the different isoforms of vitamin E, gamma tocopherol may have protective effects in bone, especially in the situation of high fat diet induced bone loss. Further examination of the mechanistic action of vitamin E isoforms on skeletal health is warranted. Funding Sources Texas Woman's University.


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