scholarly journals High-fat Overfeeding Does Not Exacerbate Rapid Changes in Forearm Glucose and Fatty Acid Balance During Immobilization

2019 ◽  
Vol 105 (1) ◽  
pp. 276-289 ◽  
Author(s):  
Marlou L Dirks ◽  
Benjamin T Wall ◽  
Britt Otten ◽  
Ana M Cruz ◽  
Mandy V Dunlop ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
High Fat Diet ◽  
Serum Insulin ◽  
Physiological Adaptation ◽  
Nonesterified Fatty Acid ◽  
Model Assessment ◽  
High Fat ◽  
Cast Immobilization ◽  
Induce Insulin Resistance

Abstract Context Physical inactivity and high-fat overfeeding have been shown to independently induce insulin resistance. Objective Establish the contribution of muscle disuse and lipid availability to the development of inactivity-induced insulin resistance. Design, Setting, Participants, and Interventions 20 healthy males underwent 7 days of forearm cast immobilization combined with a fully controlled eucaloric diet (n = 10, age 23 ± 2 yr, body mass index [BMI] 23.8 ± 1.0 kg·m-2) or a high-fat diet (HFD) providing 50% excess energy from fat (high-fat diet, n = 10, age 23 ± 2 yr, BMI 22.4 ± 0.8 kg·m-2). Main Outcome Measures Prior to casting and following 2 and 7 days of immobilization, forearm glucose uptake (FGU) and nonesterified fatty acid (NEFA) balance were assessed using the arterialized venous–deep venous (AV-V) forearm balance method following ingestion of a mixed macronutrient drink. Results 7 days of HFD increased body weight by 0.9 ± 0.2 kg (P = 0.002), but did not alter fasting, arterialized whole-blood glucose and serum insulin concentrations or the associated homeostatic model assessment of insulin resistance or Matsuda indices. Two and 7 days of forearm immobilization led to a 40 ± 7% and 52 ± 7% decrease in FGU, respectively (P < 0.001), with no difference between day 2 and 7 and no effect of HFD. Forearm NEFA balance tended to increase following 2 and 7 days of immobilization (P = 0.095). Conclusions Forearm immobilization leads to a rapid and substantial decrease in FGU, which is accompanied by an increase in forearm NEFA balance but is not exacerbated by excess dietary fat intake. Altogether, our data suggest that disuse-induced insulin resistance of glucose metabolism occurs as a physiological adaptation in response to the removal of muscle contraction.

scholarly journals Effects of Omega-3 Fatty Acids on Insulin Resistance in an Ovariectomized Mouse Model of Diet-Induced Obesity Treated with Chemotherapy

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 345-345
Author(s):  
Kate Ormiston ◽  
Zihan Zhang ◽  
Kelly Murphy ◽  
A Courtney DeVries ◽  
Maryam Lustberg ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Blood Glucose ◽  
Body Fat ◽  
High Fat Diet ◽  
Serum Insulin ◽  
Model Assessment ◽  
Omega 3 ◽  
High Fat ◽  
Body Weights

Abstract Objectives Our objective was to examine effects of dietary enrichment of eicosapentaenoic acid + docosahexaenoic acid (EPA + DHA) on high fat diet-induced insulin resistance during chemotherapy. Methods Adult, female C57Bl/6 mice (n = 48) were assigned to 1 of 3 diets; low-fat diet (LF; 10% kcals fat), high-fat diet (HF; 45% kcals fat), or HF diet with omega-3 s (HF n-3; 2% kcals EPA + DHA) for 7 weeks. Mice received vehicle or chemotherapy injections (doxorubicin + cyclophosphamide), by tail vein at week 4 and 6. Food intake and body weights were recorded. Fasted blood glucose and serum insulin were measured weekly.  Homeostatic model assessment of insulin resistance (HOMA-IR) was calculated. Body composition was measured using Echo MRI. Data were analyzed using ANOVA; p < 0.05 was considered significant. Results Total kilocalories significantly differed by group (p < 0.001); HF and HF n-3 groups consumed more than the LF group (p < 0.001, p < 0.0001; respectively). Obesity was induced prior to first injection with body weights being significantly different (p < 0.01); the LF group weighed less than the HF n-3 group (p < 0.01), and there was a similar trend between LF and HF groups (p = 0.0519). Body weights at sacrifice significantly differed (p < 0.0001); chemotherapy mice weighed less than vehicle (p < 0.0001). Percent body fat at sacrifice significantly differed (p < 0.0001); chemotherapy mice had less fat than vehicle (p < 0.0001), and the LF group had less fat than HF  (p < 0.01) and HF n-3 group (p < 0.01). Blood glucose significantly differed at sacrifice (p < 0.01); chemotherapy mice had lower glucose than vehicle (p < 0.05) and HF group had higher glucose than LF group (p < 0.01). HOMA-IR scores at sacrifice significantly differed (p < 0.05); chemotherapy mice had lower scores than vehicle  (p < 0.05) and mice on the LF and HF n-3 diets had lower scores than the HF diet (p < 0.01; p < 0.05 respectively). Conclusions Chemotherapy lowered body weight and body fat in mice, potentially contributing to decreases in blood glucose and insulin resistance. EPA + DHA enrichment of a HF diet reduced insulin resistance in mice comparable to a LF diet group. This occurred in both chemotherapy and vehicle treated mice, despite LF diet-fed mice having lower body weight and adiposity. Underlying mechanisms are being investigated. Funding Sources NIH #5R01CA18994.

scholarly journals Neurodegeneration in an animal model of Parkinson's disease is exacerbated by a high-fat diet

2010 ◽  
Vol 299 (4) ◽  
pp. R1082-R1090 ◽  
Author(s):  
Jill K. Morris ◽  
Gregory L. Bomhoff ◽  
John A. Stanford ◽  
Paige C. Geiger
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Animal Model ◽  
Locomotor Activity ◽  
Substantia Nigra ◽  
High Fat Diet ◽  
Model Assessment ◽  
High Fat

Despite numerous clinical studies supporting a link between type 2 diabetes (T2D) and Parkinson's disease (PD), the clinical literature remains equivocal. We, therefore, sought to address the relationship between insulin resistance and nigrostriatal dopamine (DA) in a preclinical animal model. High-fat feeding in rodents is an established model of insulin resistance, characterized by increased adiposity, systemic oxidative stress, and hyperglycemia. We subjected rats to a normal chow or high-fat diet for 5 wk before infusing 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle. Our goal was to determine whether a high-fat diet and the resulting peripheral insulin resistance would exacerbate 6-OHDA-induced nigrostriatal DA depletion. Prior to 6-OHDA infusion, animals on the high-fat diet exhibited greater body weight, increased adiposity, and impaired glucose tolerance. Two weeks after 6-OHDA, locomotor activity was tested, and brain and muscle tissue was harvested. Locomotor activity did not differ between the groups nor did cholesterol levels or measures of muscle atrophy. High-fat-fed animals exhibited higher homeostatic model assessment of insulin resistance (HOMA-IR) values and attenuated insulin-stimulated glucose uptake in fast-twitch muscle, indicating decreased insulin sensitivity. Animals in the high-fat group also exhibited greater DA depletion in the substantia nigra and the striatum, which correlated with HOMA-IR and adiposity. Decreased phosphorylation of HSP27 and degradation of IκBα in the substantia nigra indicate increased tissue oxidative stress. These findings support the hypothesis that a diet high in fat and the resulting insulin resistance may lower the threshold for developing PD, at least following DA-specific toxin exposure.

scholarly journals PO-193 Exercise training decreased lipid accumulation in murine skeletal muscle through Sestrin2-mediated SHIP2-JNK signaling pathway

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Tianyi Wang ◽  
Song Huang ◽  
Xiao Han ◽  
Sujuan Liu ◽  
Yanmei Niu ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
Exercise Training ◽  
High Fat Diet ◽  
De Novo ◽  
Underlying Mechanism ◽  
Wild Type ◽  
High Fat

Objective Obesity is becoming increasingly prevalent and is an important contributor to the worldwide burden of diseases. It is widely accepted that exercise training is beneficial for the prevention and treatment of obesity. However, the underlying mechanism by which exercise training improving skeletal muscle lipid metabolism is still not fully described. Sestrins (Sestrin1-3) are highly conserved stress-inducible protein. Concomitant ablation of Sestrin2 and Sestrin3 has been reported to provoke hepatic mTORC1/S6K1 activation and insulin resistance even without nutritional overload and obesity, implicating that Sestrin2 and Sestrin3 have an important homeostatic function in the control of mammalian glucose and lipid metabolism. Our previous results demonstrated that physical exercise increased Sestrin2 expression in murine skeletal muscle, while the role of Sestrin2 in regulating lipid metabolism remains unknown.  SH2 domain containing inositol 5-phosphatase (SHIP2) acts as a negative regulator of the insulin signaling both in vitro and in vivo. An increased expression of SHIP2 inhibits the insulin-induced Akt activation, glucose uptake, and glycogen synthesis in 3T3-L1 adipocytes, L6 myotubes and tissues of animal models. Alterations of SHIP2 expression and/or enzymatic function appear to have a profound impact on the development of insulin resistance. However, the regulatory function of SHIP2 in lipid metabolism after exercise remains unclear. It has been reported that SHIP2 modulated lipid metabolism through regulating the activity of c-Jun N-terminal kinase (JNK) and Sterol regulatory element-binding protein-1 (SREBP-1). JNK is a subclass of mitogen-activated protein kinase (MAPK) signaling pathway in mammalian cells and plays a crucial role in metabolic changes and inflammation associated with a high-fat diet. Inhibition of JNK reduces lipid deposition and proteins level of fatty acid de novo synthesis in liver cells. It has been reported that Sestrin2 regulated the phosphorylation of JNK, however the underlying mechanism remains unclear. SREBP-1 is important in regulating cholesterol biosynthesis and uptake and fatty acid biosynthesis, and SREBP-1 expression produces two different isoforms, SREBP-1a and SREBP-1c. SREBP-1c is responsible for regulating the genes required for de novo lipogenesis and its expression is regulated by insulin. SREBP-1a regulates genes related to lipid and cholesterol production and its activity is regulated by sterol levels in the cell. Altogether, the purpose of this study was to explore the effect and underlying mechanism of Sestrin2 on lipid accumulation after exercise training. Methods Male wild type and SESN2−/− mice were divided into normal chow (NC) and high-fat diet (HFD) groups to create insulin resistance mice model. After 8 weeks the IR model group was then divided into HFD sedentary control and HFD exercise groups (HE). Mice in HE group underwent 6-week treadmill exercise to reveal the effect of exercise training on lipid metabolism in insulin resistance model induced by HFD. We explored the mechanism through which Sestrin2 regulated lipid metabolism in vitro by supplying palmitate, overexpressing or inhibiting SESNs, SHIP2 and JNK in myotubes. Results We found that 6-week exercise training decreased body weight, BMI and fat mass in wild type and SESN2-/- mice after high-fat diet (HFD) feeding. And exercise training decreased the level of plasma glucose, serum insulin, triglycerides and free fatty acids in wild type but not in Sestrin2-/- mice. Lipid droplet in skeletal muscle was also decreased in wild type but did not in Sestrin2-/- mice. Moreover, exercise training increased the proteins expression involved in fatty acid oxidation and decreased the proteins which related to fatty acid de novo synthesis. The results of oil red staining and the change of proteins related to fatty acid de novo synthesis and beta oxidation in myotubes treated with palmitate, Ad-SESN2 and siRNA-Sestrin2 were consisted with the results in vivo, which suggested that Sestrin2 was a key regulator in lipid metabolism. Exercise training increased Sestrin2 expression and reversed up-regulation of SHIP2 and pJNK induced by HFD in wild type mice but not in Sestrin2-/- mice. In parallel, overexpression of Sestrin2 decreased the level of SHIP2 and pJNK induced by palmitate while Sestrin2 knock down by siRNA-Sestrin2 treatment did not change the expression of SHIP2 and pJNK, which suggested that Sestrin2 modulated SHIP2 and JNK in the state of abnormal lipid metabolism. Inhibition of SHIP2 reduced the activity of JNK, increased lipid accumulation and the proteins of fatty acid synthesis after palmitate treatment and over expression of Sestrin2, which suggest that Sestrin2 modulated lipid metabolism through SHIP2/JNK pathway. Conclusions Sestrin2 plays an important role in improving lipid metabolism after exercise training, and Sestrin2 regulates lipid metabolism by SHIP2-JNK pathway in skeletal muscle.

scholarly journals Hypoglycemic effects and mechanisms of electroacupuncture on insulin resistance

2014 ◽  
Vol 307 (3) ◽  
pp. R332-R339 ◽  
Author(s):  
Jieyun Yin ◽  
Jian Kuang ◽  
Manisha Chandalia ◽  
Demidmaa Tuvdendorj ◽  
Batbayar Tumurbaatar ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
Blood Glucose ◽  
Insulin Sensitivity ◽  
Free Fatty Acid ◽  
Glucose Tolerance ◽  
High Fat Diet ◽  
Postprandial Glucose ◽  
Tolerance Test ◽  
High Fat

The aim of this study was to investigate effects and mechanisms of electroacupuncture (EA) on blood glucose and insulin sensitivity in mice fed a high-fat diet. Both wild-type (WT) and adipose ectonucleotide pyrophosphate phosphodiesterase (ENPP1) transgenic (TG) mice were fed a high-fat diet for 12 wk; for each mouse, an intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (ITT) were performed with or without EA at abdomen or auricular areas. A high-fat diet-induced insulin resistance in both WT and TG mice. In the WT mice, EA at 3 Hz and 15 Hz, but not at 1 Hz or 100 Hz, via CV4+CV12 significantly reduced postprandial glucose levels; EA at 3 Hz was most potent. The glucose level was reduced by 61.7% at 60 min and 74.5% at 120 min with EA at 3 Hz (all P < 0.001 vs. control). Similar hypoglycemic effect was noted in the TG mice. On the contrary, EA at auricular points increased postprandial glucose level ( P < 0.03). 4). EA at 3 Hz via CV4+CV12 significantly enhanced the decrease of blood glucose after insulin injection, suggesting improvement of insulin sensitivity. Plasma free fatty acid was significantly suppressed by 42.5% at 15 min and 50.8% at 30 min with EA ( P < 0.01) in both WT and TG mice. EA improves glucose tolerance in both WT and TG mice fed a high-fat diet, and the effect is associated with stimulation parameters and acupoints and is probably attributed to the reduction of free fatty acid.

Electroacupuncture Mitigates Endothelial Dysfunction via Effects on the Pi3K/Akt Signalling Pathway in High Fat Diet-Induced Insulin-Resistant Rats

2018 ◽  
Vol 36 (3) ◽  
pp. 162-169 ◽  
Author(s):  
Danchun Lan ◽  
Nenggui Xu ◽  
Jian Sun ◽  
Zhixing Li ◽  
Rongzhen Liao ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Endothelial Dysfunction ◽  
Pancreatic Islet ◽  
High Fat Diet ◽  
Negative Impact ◽  
Fasting Blood Glucose ◽  
Signalling Pathway ◽  
Control Group ◽  
Model Assessment ◽  
High Fat

Objective To investigate the effect of electroacupuncture (EA) on endothelial dysfunction related to high fat diet (HFD)-induced insulin resistance through the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt) signalling pathway. Methods Twenty-four male Sprague-Dawley rats were fed a regular diet (Control group, n=8) or a HFD (n=16) for 12 weeks to induce an insulin resistance model. HFD-fed rats were divided into two groups that remained untreated (HFD group, n=8) or received electroacupuncture (HFD+EA group, n=8). EA was applied at PC6, ST36, SP6 and BL23. At the end of the experiment, fasting blood glucose (FBG), serum insulin (FINS), serum C-peptide (C-P) and homeostatic model assessment of insulin resistance (HOMA-IR) indices were determined. Pancreatic islet samples were subjected to histopathological examination. The thoracic aorta was immunostained with anti-rat insulin receptor substrate (IRS)-1, Akt and endothelial nitric oxide synthase (eNOS) antibodies. mRNA and protein expression of IRS-1, PI3K, Akt2 and eNOS in the vascular endothelium were determined by real-time PCR and Western blot analysis, respectively. Results The bodyweight increase of the HFD+EA group was smaller than that of the untreated HFD group. Compared with the HFD group, the levels of FBG, FINS, C-P and HOMA-IR in the HFD+EA group decreased significantly (P<0.01). Histopathological evaluation indicated that EA improved pancreatic islet inflammation. The expression of endothelial markers, such as IRS-1, PI3K, Akt2 and eNOS, decreased in the HFD group, while EA treatment appeared to ameliorate the negative impact of diet. Conclusion EA may improve insulin resistance and attenuate endothelial dysfunction, and therefore could play a potential role in the prevention or treatment of diabetic complications and cardiovascular disease through the PI3K/Akt signalling pathway.

scholarly journals Effects of three different conjugated linoleic acid preparations on insulin signalling, fat oxidation and mitochondrial function in rats fed a high-fat diet

2007 ◽  
Vol 98 (2) ◽  
pp. 264-275 ◽  
Author(s):  
Joo Sun Choi ◽  
In-Uk Koh ◽  
Myeong Ho Jung ◽  
Jihyun Song
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Mitochondrial Function ◽  
High Fat Diet ◽  
Insulin Signalling ◽  
Fat Oxidation ◽  
Acid Oxidation ◽  
High Fat ◽  
Cla Isomers

To investigate the effects of three different conjugated linoleic acid (CLA) preparations containing different ratios of CLA isomers on insulin signalling, fatty acid oxidation and mitochondrial function, Sprague–Dawley rats were fed a high-fat diet either unsupplemented or supplemented with one of three CLA preparations at 1 % of the diet for 8 weeks. The first CLA preparation contained approximately 30 % cis-9, trans-11 (c9, t11)-CLA isomer and 40 % trans-10, cis-12 (t10, c12)-CLA isomer (CLA-mix). The other two preparations were an 80:20 mix (c9, t11-CLA-mix) or a 10:90 mix of two CLA isomers (t10, c12-CLA-mix). Insulin resistance was decreased in all three supplemented groups based on the results of homeostasis model assessment and the revised quantitative insulin-sensitivity check index. The phosphorylation of insulin receptor substrate-1 on serine decreased in the livers of all three supplemented groups, while subsequent Akt phosphorylation increased only in the t10, c12-CLA-mix group. Both the c9, t11-CLA-mix and the t10, c12-CLA-mix increased the expression of hepatic adiponectin receptors R1 and 2, which are thought to enhance insulin sensitivity and fat oxidation. The c9, t11-CLA-mix increased protein and mRNA levels of PPARα, acyl-CoA oxidase and uncoupling protein, which are involved in fatty acid oxidation and energy dissipation. The c9, t11-CLA-mix enhanced mitochondrial function and protection against oxidative stress by increasing the activities of cytochrome c oxidase, manganese-superoxide dismutase, glutathione peroxidase, and glutathione reductase and the level of GSH. In conclusion, all three CLA preparations reduced insulin resistance. Among them, the c9, t11-CLA-mix was the most effective based on the parameters reflecting insulin resistance and fat oxidation, and mitochondrial antioxidative enzyme activity in the liver.

scholarly journals Effects of Distinct n-6 to n-3 Polyunsaturated Fatty Acid Rations on Insulin Resistant and AD-like Phenotypes in High-Fat Diets-Fed APP/PS1 Transgenic Mice

2021 ◽  
Author(s):  
Xiaojun Ma ◽  
Yujie Guo ◽  
Pengfei Li ◽  
Jingjing Xu ◽  
Shengqi Dong ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
Protein Expression ◽  
Signaling Pathway ◽  
Inflammatory Cytokines ◽  
Insulin Signaling ◽  
High Fat Diet ◽  
High Fat ◽  
Pufa Ratio ◽  
Pro Inflammatory Cytokines

Abstract Background: Type 2 diabetes mellitus (T2DM) and Alzheimer’s disease (AD) are two prevalent diseases with comparable pathophysiological features and genetic predisposition. Polyunsaturated fatty acids (PUFAs) are essential in maintaining normal brain function. However, little is known about the impact of dietary n-6/n-3 PUFA ratio on AD-like pathology, especially in high-fat diet (HFD)-fed AD model mice. Methods: In the present study, the APP/PS1 mice were treated with 60% HFD for 3.5 months to induced insulin resistance. After that, 45% HFD with different n-6/n-3 PUFA ratios (n-6/n-3=1:1, 5:1 or 16:1) was applied for additional 3.5 months treatment. Following the dietary intervention, the behavior of mice was observed using the Water maze. Following behavioral testing, the animals were euthanized, and serum and tissue samples were collected for biochemical, histological and pathological analyses and evaluation. Cortical fatty acid profile was measured by gas chromatography. Western Blot and immunohistochemistry methods were used to detect protein expression of molecules related to AD pathology and insulin signaling pathway(s) in the brain sample tissues. Immunofluorescence assay was used to uncover the expression and migration of NF-κB in the cortex. qPCR method was applied to determine the gene expression of cortical pro-inflammatory cytokines.Results: HFD caused insulin resistance, increased serum IL-6 and TNF-α level, elevated cortical soluble Aβ1-40, Aβ1-42 content, and increased brain n-6/n-3 PUFAs ratio in APP/PS1 mice. Increased APP and BACE1 protein expression and p-IR/IR ratio, but decreased pro-inflammatory cytokines mRNA expression was observed in the cortex from 60% HFD-fed APP/PS1 mice. N-3 PUFAs rich diet (n-6/n-3=1:1) relieved insulin resistance and hyperlipidemia induced by 60% HFD. Cortical soluble Aβ1-40 and Aβ1-42 contents, the expression of cortical APP, GLUT3, insulin metabolism related molecules, and NF-κB pathway downstream pro-inflammatory cytokines showed a dietary n-6/n-3 PUFAs ratio-dependent way, indicating that dietary n-6/n-3 PUFA ratio plays a critical role in modifying the responses of serum inflammatory cytokine, AD pathology, cortical n-6/n-3 PUFAs ratio, insulin signaling and neuroinflammation to HFD treatment.Conclusion: Dietary n-6/n-3 PUFA ratio play an important role in modifying AD pathophysiology, insulin signaling pathway, and neuro-inflammation response to high fat diet treatment in brain.

scholarly journals Replacing Part of Glucose with Galactose in the Postweaning Diet Protects Female But Not Male Mice from High-Fat Diet–Induced Adiposity in Later Life

2019 ◽  
Vol 149 (7) ◽  
pp. 1140-1148 ◽  
Author(s):  
Lianne M S Bouwman ◽  
José M S Fernández-Calleja ◽  
Inge van der Stelt ◽  
Annemarie Oosting ◽  
Jaap Keijer ◽  
...  
Keyword(s):  
Body Weight ◽  
Insulin Receptor ◽  
High Fat Diet ◽  
Serum Insulin ◽  
Later Life ◽  
Partial Replacement ◽  
Model Assessment ◽  
High Fat ◽  
Female Mice ◽  
Subcutaneous White Adipose Tissue

ABSTRACT Background Duration of breastfeeding is positively associated with decreased adiposity and increased metabolic health in later life, which might be related to galactose. Objective The aim of this study was to investigate if partial replacement of glucose with galactose in the postweaning diet had a metabolic programming effect. Methods Male and female mice (C57BL/6JRccHsd) received an isocaloric diet (16 energy% fat; 64 energy% carbohydrates; 20 energy% protein) with either glucose (32 energy%) (GLU) or glucose + galactose (GLU + GAL, 16 energy% each) for 3 wk postweaning. Afterwards, all mice were switched to the same 40 energy% high-fat diet (HFD) for 9 wk to evaluate potential programming effects in an obesogenic environment. Data were analyzed within sex. Results Female body weight (−14%) and fat mass (−47%) were significantly lower at the end of the HFD period (both P < 0.001) among those fed GLU + GAL than among those fed GLU; effects in males were in line with these findings but nonsignificant. Food intake was affected in GLU + GAL–fed females (+8% on postweaning diet, −9% on HFD) compared with GLU-fed females, but not for hypothalamic transcript levels at endpoint. Also, in GLU + GAL–fed females, serum insulin concentrations (−48%, P  < 0.05) and the associated homeostasis model assessment of insulin resistance (HOMA-IR) were significantly lower ( P < 0.05) at endpoint, but there were no changes in pancreas morphology. In GLU + GAL–fed females, expression of insulin receptor substrate 2 (Irs2) (−27%, P  < 0.01 ; −44%, P  < 0.001) and the adipocyte size markers leptin (Lep) (−40%, P  < 0.05; −63% , P  < 0.05) and mesoderm-specific transcript homolog protein (Mest) (−80%, P < 0.05; −72%, P  < 0.05) was lower in gonadal and subcutaneous white adipose tissue (WAT), respectively. Expression of insulin receptor substrate1 (Irs1) (−24%, P  < 0.05) was only lower in subcutaneous WAT in GLU + GAL–fed females. Conclusions Partial replacement of glucose with galactose, resulting in a 1:1 ratio mimicking lactose, in a 3-wk postweaning diet lowered body weight, adiposity, HOMA-IR, and expression of WAT insulin signaling in HFD-challenged female mice in later life. This suggests that prolonged galactose intake may improve metabolic and overall health in later life.

scholarly journals Tumor Necrosis Factor Alpha Knockout Promotes Adipose Fatty Acid Oxidation and Attenuates Insulin Resistance and Hepatic Steatosis in High Fat Diet-Fed Mice

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1705-1705
Author(s):  
Seok-Yeong Yu ◽  
Jinchao Li ◽  
Zhenhua Liu ◽  
Young-Cheul Kim
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
High Fat Diet ◽  
Tumor Necrosis ◽  
Acid Metabolism ◽  
Acid Oxidation ◽  
High Fat ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor

Abstract Objectives Substantial evidence indicates that adipose tissue (AT) dysfunction and lipid spillover in obesity promote insulin resistance and non-alcoholic fatty liver disease. Tumor necrosis factor alpha (TNFα) is one of the pro-inflammatory cytokines overexpressed in obesity and its knockout (KO) attenuates diet-induced adiposity, lipid deposition in the liver and insulin resistance. However, the potential roles played by TNFα in fatty acid metabolism in AT have been incompletely understood. The objective of this study was to investigate the role of TNFα in obesity-induced insulin resistance with the goal of providing a potential target for therapeutics. Methods Three groups of wild type (WT) or TNFα KO male mice on the same B6 genetic background were fed designated diets for 16 weeks; WT fed a low-fat diet (LFD-WT), WT fed a high-fat diet (HFD-WT), and TNFα KO fed a HFD (HFD-TNFα KO). Blood concentrations of glucose and insulin and hepatic triacylglycerol (TG) levels were measured. The expression of genes involved in fatty acid and TG synthesis and fatty acid oxidation (FAO) was measured in epididymal white AT (eWAT). Results Compared to the LFD-fed mice, HFD-WT group had a significantly higher levels of blood glucose and insulin, and hepatic TG (P &lt; 0.05). TNFα KO mice significantly improved HFD-induced hyperglycemia, hyperinsulinemia and hepatic TG accumulation (P &lt; 0.05). In eWAT, TNFα ablation did not affect the expression of de novo fatty-acid synthesis-related genes, but significantly increased the expression of TG synthesis-related genes (p &lt; 0.05). Moreover, TNFα KO presented a significantly increased expression of the FAO-related gene, CPT1, with a concomitant increase in the expression of glucose transporter 4 (GLUT4) and oxidative phosphorylation-related genes (CS and mt-CO1) (P &lt; 0.05). Further evidence of the inhibition of fatty acid metabolism by TNFα includes a significant suppression of CPT1 as well as TG synthesis-related genes (P &lt; 0.05) in 3T3-L1 adipocytes treated with TNFα. Conclusions These data indicate that antagonizing TNFα may mitigate diet-induced insulin resistance and hepatic steatosis by promoting FAO in obese AT. Funding Sources N/A.

scholarly journals Electroacupuncture Mitigates Skeletal Muscular Lipid Metabolism Disorder Related to High-Fat-Diet Induced Insulin Resistance through the AMPK/ACC Signaling Pathway

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Zhixing Li ◽  
Danchun Lan ◽  
Haihua Zhang ◽  
Hongtao Zhang ◽  
Xiaozhuan Chen ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
High Fat Diet ◽  
Control Group ◽  
Sensitivity Index ◽  
Model Assessment ◽  
Sprague Dawley ◽  
High Fat ◽  
Lipid Metabolism Disorder ◽  
Metabolism Disorder

The aim of this work is to investigate the effect of electroacupuncture (EA) on insulin sensitivity in high-fat diet (HFD) induced insulin resistance (IR) rats and to evaluate expression of AMPK/ACC signaling components. Thirty-two male Sprague-Dawley rats were randomized into control group, HFD group, HFD+Pi (oral gavage of pioglitazone) group, and HFD+EA group. Acupuncture was subcutaneously applied to Zusanli (ST40) and Sanyinjiao (SP6). For Zusanli (ST40) and Sanyinjiao (SP6), needles were connected to an electroacupuncture (EA) apparatus. Fasting plasma glucose was measured by glucose oxidase method. Plasma fasting insulin (FINS) and adiponectin (ADP) were determined by ELISA. Triglyceride (TG) and cholesterol (TC) were determined by Gpo-pap. Proteins of adiponectin receptor 1 (adipoR1), AMP-activated Protein Kinase (AMPK), and acetyl-CoA carboxylase (ACC) were determined by Western blot, respectively. Compared with the control group, HFD group exhibits increased levels of FPG, FINS, and homeostatic model assessment of insulin resistance (HOMA-IR) and decreased level of ADP and insulin sensitivity index (ISI). These changes were reversed by both EA and pioglitazone. Proteins of adipoR1 and AMPK were decreased, while ACC were increased in HFD group compared to control group. Proteins of these molecules were restored back to normal levels upon EA and pioglitazone. EA can improve the insulin sensitivity of insulin resistance rats; the positive regulation of the AMPK/ACC pathway in the skeletal muscle may be a possible mechanism of EA in the treatment of IR.

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