scholarly journals Sexual Dimorphism in the Age-Induced Insulin Resistance, Liver Steatosis, and Adipose Tissue Function in Rats

2017 ◽  
Vol 8 ◽  
Author(s):  
Francisco Garcia-Carrizo ◽  
Teresa Priego ◽  
Nara Szostaczuk ◽  
Andreu Palou ◽  
Catalina Picó
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Sexual Dimorphism ◽  
Liver Steatosis

The Effects of Gymnema sylvestre in High-Fat Diet-Induced Metabolic Disorders

2017 ◽  
Vol 45 (04) ◽  
pp. 813-832 ◽  
Author(s):  
Hyeon-Jeong Kim ◽  
Sanghwa Kim ◽  
Ah Young Lee ◽  
Yoonjeong Jang ◽  
Orkhonselenge Davaadamdin ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Adipose Tissue ◽  
Dietary Supplement ◽  
High Fat Diet ◽  
Liver Steatosis ◽  
Integrated Approach ◽  
Serum Levels ◽  
Gymnema Sylvestre ◽  
High Fat

This study used an integrated approach to investigate the effects of Gymnema sylvestre (GS) extract as a functional dietary supplement with a high-fat diet. This approach examined insulin resistance, the dysfunction of adipose tissue, and liver steatosis. Male C57BL/6J mice were fed a normal chow or high-fat diet (HFD) for the acute and chronic study, in addition to GS in different doses (100, 250 and 500[Formula: see text]mg/kg body weight). Their body composition changes, serum lipid and glucose parameters, adipose and liver tissue histology, and gene expression were measured. It was found that GS significantly suppressed the increase of body weight, serum levels of lipid, insulin and leptin, and adipose tissue, and liver inflammation. GS also demonstrated hypoglycemic effects due to the amylase inhibition activity. Our results support the existence of a relationship between the HFD induced insulin resistance, adipose dysfunction and liver steatosis. In conclusion, GS works as a functional dietary supplement with preventative effects against metabolic disorder.

scholarly journals CD40 deficiency in mice exacerbates obesity-induced adipose tissue inflammation, hepatic steatosis, and insulin resistance

2013 ◽  
Vol 304 (9) ◽  
pp. E951-E963 ◽  
Author(s):  
Chang-An Guo ◽  
Sophia Kogan ◽  
Shinya U. Amano ◽  
Mengxi Wang ◽  
Sezin Dagdeviren ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Hepatic Steatosis ◽  
Immune Cell ◽  
Ex Vivo ◽  
Liver Steatosis ◽  
Epididymal Adipose Tissue ◽  
Low Grade ◽  
Wild Type ◽  
Cytokine Levels

The pathophysiology of obesity and type 2 diabetes in rodents and humans is characterized by low-grade inflammation in adipose tissue and liver. The CD40 receptor and its ligand CD40L initiate immune cell signaling promoting inflammation, but conflicting data on CD40L-null mice confound its role in obesity-associated insulin resistance. Here, we demonstrate that CD40 receptor-deficient mice on a high-fat diet display the expected decrease in hepatic cytokine levels but paradoxically exhibit liver steatosis, insulin resistance, and glucose intolerance compared with their age-matched wild-type controls. Hyperinsulinemic-euglycemic clamp studies also demonstrated insulin resistance in glucose utilization by the CD40-null mice compared with wild-type mice. In contrast to liver, adipose tissue in CD40-deficient animals harbors elevated cytokine levels and infiltration of inflammatory cells, particularly macrophages and CD8+effector T cells. In addition, ex vivo explants of epididymal adipose tissue from CD40−/−mice display elevated basal and isoproterenol-stimulated lipolysis, suggesting a potential increase of lipid efflux from visceral fat to the liver. These findings reveal that 1) CD40-null mice represent an unusual model of hepatic steatosis with reduced hepatic inflammation, and 2) CD40 unexpectedly functions in adipose tissue to attenuate its inflammation in obesity, thereby protecting against hepatic steatosis.

scholarly journals Improvement of Insulin Sensitivity after Peroxisome Proliferator-Activated Receptor-α Agonist Treatment Is Accompanied by Paradoxical Increase of Circulating Resistin Levels

Endocrinology ◽  
2006 ◽  
Vol 147 (9) ◽  
pp. 4517-4524 ◽  
Author(s):  
M. M. Haluzik ◽  
Z. Lacinova ◽  
M. Dolinkova ◽  
D. Haluzikova ◽  
D. Housa ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Mrna Expression ◽  
Liver Steatosis ◽  
Tissue Expression ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Insulin Levels ◽  
Fenofibrate Treatment ◽  
Adiponectin Mrna

We studied the effect of peroxisome proliferator-activated receptor-α (PPAR-α) activation on serum concentrations and tissue expression of resistin, adiponectin, and adiponectin receptor-1 and -2 (AdipoR1 and AdipoR2) mRNA in normal mice and mice with insulin resistance induced by lipogenic, simple-carbohydrate diet (LD). Sixteen weeks of LD feeding induced obesity with liver steatosis and increased insulin levels but did not significantly affect circulating adiponectin or resistin. Treatment with PPAR-α agonist fenofibrate decreased body weight and fat pad weight and ameliorated liver steatosis in LD-fed mice with concomitant reduction in blood glucose, free fatty acid, triglyceride, serum insulin levels, and homeostasis model assessment index values. Euglycemic-hyperinsulinemic clamp demonstrated the development of whole-body and liver insulin resistance in LD-fed mice, which were both normalized by fenofibrate. Fenofibrate treatment markedly increased circulating resistin levels on both diets and adiponectin levels in chow-fed mice only. Fat adiponectin mRNA expression was not affected by fenofibrate treatment. Resistin mRNA expression increased in subcutaneous but not gonadal fat after fenofibrate treatment. In addition to fat, a significant amount of adiponectin mRNA was also expressed in the muscle. This expression markedly increased after fenofibrate treatment in chow- but not in LD-fed mice. Adipose tissue expression of AdipoR1 mRNA was significantly reduced in LD-fed mice and increased after fenofibrate treatment. In conclusion, PPAR-α activation ameliorated the development of insulin resistance in LD-fed mice despite a major increase in serum resistin levels. This effect could be partially explained by increased AdipoR1 expression in adipose tissue after fenofibrate treatment.

scholarly journals Depletion of CD40 on CD11c+ cells worsens the metabolic syndrome and ameliorates hepatic inflammation during NASH

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Suzanne Aarts ◽  
Myrthe Reiche ◽  
Myrthe den Toom ◽  
Marion Gijbels ◽  
Linda Beckers ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Metabolic Syndrome ◽  
Adipose Tissue ◽  
Liver Lipid ◽  
Liver Steatosis ◽  
Fine Tuning ◽  
Metabolic Dysfunction ◽  
Liver Inflammation ◽  
Genetic Ablation ◽  
The Metabolic Syndrome

Abstract The co-stimulatory CD40-CD40L dyad plays a central role in fine-tuning immune reactions, including obesity-induced inflammation. Genetic ablation of CD40L reduced adipose tissue inflammation, while absence of CD40 resulted in aggravated metabolic dysfunction in mice. During obesity, CD40 expressing CD11c+ dendritic cells (DC) and macrophages accumulate in adipose tissue and liver. We investigated the role of CD40+CD11c+ cells in the metabolic syndrome and nonalcoholic steatohepatitis (NASH). DC-CD40-ko mice (CD40fl/flCD11ccre) mice were subjected to obesity or NASH. Obesity and insulin resistance were induced by feeding mice a 54% high fat diet (HFD). NASH was induced by feeding mice a diet containing 40% fat, 20% fructose and 2% cholesterol. CD40fl/flCD11ccre mice fed a HFD displayed increased weight gain, increased adipocyte size, and worsened insulin resistance. Moreover, CD40fl/flCD11ccre mice had higher plasma and hepatic cholesterol levels and developed profound liver steatosis. Overall, regulatory T cell numbers were decreased in these mice. In NASH, absence of CD40 on CD11c+ cells slightly decreased liver inflammation but did not affect liver lipid accumulation. Our experiments suggest that CD40 expressing CD11c+ cells can act as a double-edged sword: CD40 expressing CD11c+ cells contribute to liver inflammation during NASH but are protective against the metabolic syndrome via induction of regulatory T cells.

scholarly journals The Relevance of Thimet Oligopeptidase in the Regulation of Energy Metabolism and Diet-Induced Obesity

Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 321 ◽  
Author(s):  
Mayara C. F. Gewehr ◽  
Alexandre A. S. Teixeira ◽  
Bruna A. C. Santos ◽  
Luana A. Biondo ◽  
Fábio C. Gozzo ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Energy Metabolism ◽  
Liver Steatosis ◽  
Alcoholic Fatty Liver ◽  
Metabolism Regulation ◽  
Diet Induced Obesity ◽  
Expression Of Genes ◽  
Thimet Oligopeptidase ◽  
Functional Peptides

Thimet oligopeptidase (EC 3.4.24.15; EP24.15; THOP1) is a potential therapeutic target, as it plays key biological functions in processing biologically functional peptides. The structural conformation of THOP1 provides a unique restriction regarding substrate size, in that it only hydrolyzes peptides (optimally, those ranging from eight to 12 amino acids) and not proteins. The proteasome activity of hydrolyzing proteins releases a large number of intracellular peptides, providing THOP1 substrates within cells. The present study aimed to investigate the possible function of THOP1 in the development of diet-induced obesity (DIO) and insulin resistance by utilizing a murine model of hyperlipidic DIO with both C57BL6 wild-type (WT) and THOP1 null (THOP1−/−) mice. After 24 weeks of being fed a hyperlipidic diet (HD), THOP1−/− and WT mice ingested similar chow and calories; however, the THOP1−/− mice gained 75% less body weight and showed neither insulin resistance nor non-alcoholic fatty liver steatosis when compared to WT mice. THOP1−/− mice had increased adrenergic-stimulated adipose tissue lipolysis as well as a balanced level of expression of genes and microRNAs associated with energy metabolism, adipogenesis, or inflammation. Altogether, these differences converge to a healthy phenotype of THOP1−/− fed a HD. The molecular mechanism that links THOP1 to energy metabolism is suggested herein to involve intracellular peptides, of which the relative levels were identified to change in the adipose tissue of WT and THOP1−/− mice. Intracellular peptides were observed by molecular modeling to interact with both pre-miR-143 and pre-miR-222, suggesting a possible novel regulatory mechanism for gene expression. Therefore, we successfully demonstrated the previously anticipated relevance of THOP1 in energy metabolism regulation. It was suggested that intracellular peptides were responsible for mediating the phenotypic differences that are described herein by a yet unknown mechanism of action.

scholarly journals Molecular Insulin Actions Are Sexually Dimorphic in Lipid Metabolism

2021 ◽  
Vol 12 ◽  
Author(s):  
Rosa Isela Ortiz-Huidobro ◽  
Myrian Velasco ◽  
Carlos Larqué ◽  
Rene Escalona ◽  
Marcia Hiriart
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Sexual Dimorphism ◽  
Energy Homeostasis ◽  
Molecular Mechanisms ◽  
Metabolic Diseases ◽  
Critical Role ◽  
Metabolic Dysfunction ◽  
Anabolic Hormone ◽  
Obesity And Diabetes

The increment in energy-dense food and low physical activity has contributed to the current obesity pandemic, which is more prevalent in women than in men. Insulin is an anabolic hormone that regulates the metabolism of lipids, carbohydrates, and proteins in adipose tissue, liver, and skeletal muscle. During obesity, nutrient storage capacity is dysregulated due to a reduced insulin action on its target organs, producing insulin resistance, an early marker of metabolic dysfunction. Insulin resistance in adipose tissue is central in metabolic diseases due to the critical role that this tissue plays in energy homeostasis. We focused on sexual dimorphism on the molecular mechanisms of insulin actions and their relationship with the physiology and pathophysiology of adipose tissue. Until recently, most of the physiological and pharmacological studies were done in males without considering sexual dimorphism, which is relevant. There is ample clinical and epidemiological evidence of its contribution to the establishment and progression of metabolic diseases. Sexual dimorphism is a critical and often overlooked factor that should be considered in design of sex-targeted therapeutic strategies and public health policies to address obesity and diabetes.

scholarly journals Adipose tissue insulin resistance due to loss of PI3K p110α leads to decreased energy expenditure and obesity

2014 ◽  
Vol 306 (10) ◽  
pp. E1205-E1216 ◽  
Author(s):  
Victoria L. B. Nelson ◽  
Ya-Ping Jiang ◽  
Kathleen G. Dickman ◽  
Lisa M. Ballou ◽  
Richard Z. Lin
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Energy Expenditure ◽  
Brown Adipose Tissue ◽  
Insulin Signaling ◽  
Uncoupling Protein ◽  
Critical Role ◽  
Liver Steatosis ◽  
Cellular Respiration ◽  
Brown Adipose

Adipose tissue is a highly insulin-responsive organ that contributes to metabolic regulation. Insulin resistance in the adipose tissue affects systemic lipid and glucose homeostasis. Phosphoinositide 3-kinase (PI3K) mediates downstream insulin signaling in adipose tissue, but its physiological role in vivo remains unclear. Using Cre recombinase driven by the aP2 promoter, we created mice that lack the class 1A PI3K catalytic subunit p110α or p110β specifically in the white and brown adipose tissue. The loss of p110α, not p110β, resulted in increased adiposity, glucose intolerance and liver steatosis. Mice lacking p110α in adipose tissue exhibited a decrease in energy expenditure but no change in food intake or activity compared with control animals. This low energy expenditure is a consequence of low cellular respiration in the brown adipocytes caused by a decrease in expression of key mitochondrial genes including uncoupling protein-1. These results illustrate a critical role of p110α in the regulation of energy expenditure through modulation of cellular respiration in the brown adipose tissue and suggest that compromised insulin signaling in adipose tissue might be involved in the onset of obesity.

scholarly journals Impact of tissue macrophage proliferation on peripheral and systemic insulin resistance in obese mice with diabetes

2020 ◽  
Vol 8 (1) ◽  
pp. e001578
Author(s):  
Yutaro Morita ◽  
Takafumi Senokuchi ◽  
Sarie Yamada ◽  
Toshiaki Wada ◽  
Tatsuya Furusho ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Liver Steatosis ◽  
Histological Changes ◽  
Tissue Macrophage ◽  
Systemic Insulin Resistance

IntroductionObesity-related insulin resistance is a widely accepted pathophysiological feature in type 2 diabetes. Systemic metabolism and immunity are closely related, and obesity represents impaired immune function that predisposes individuals to systemic chronic inflammation. Increased macrophage infiltration and activation in peripheral insulin target tissues in obese subjects are strongly related to insulin resistance. Using a macrophage-specific proliferation inhibition mouse model (mac-p27Tg), we previously reported that suppressed plaque inflammation reduced atherosclerosis and improved plaque stabilization. However, the direct evidence that proliferating macrophages are responsible for inducing insulin resistance was not provided.Research design and methodsThe mac-p27Tg mice were fed a high-fat diet, and glucose metabolism, histological changes, macrophage polarization, and tissue functions were investigated to reveal the significance of tissue macrophage proliferation in insulin resistance and obesity.ResultsThe mac-p27Tg mice showed improved glucose tolerance and insulin sensitivity, along with a decrease in the number and ratio of inflammatory macrophages. Obesity-induced inflammation and oxidative stress was attenuated in white adipose tissue, liver, and gastrocnemius. Histological changes related to insulin resistance, such as liver steatosis/fibrosis, adipocyte enlargement, and skeletal muscle fiber transformation to fast type, were ameliorated in mac-p27Tg mice. Serum tumor necrosis factor alpha and free fatty acid were decreased, which might partially impact improved insulin sensitivity and histological changes.ConclusionsMacrophage proliferation in adipose tissue, liver, and skeletal muscle was involved in promoting the development of systemic insulin resistance. Controlling the number of tissue macrophages by inhibiting macrophage proliferation could be a therapeutic target for insulin resistance and type 2 diabetes.

scholarly journals Sexual dimorphism in insulin resistance in a metabolic syndrome rat model

2020 ◽  
Vol 9 (9) ◽  
pp. 890-902
Author(s):  
Myrian Velasco ◽  
Rosa Isela Ortiz-Huidobro ◽  
Carlos Larqué ◽  
Yuriko Itzel Sánchez-Zamora ◽  
José Romo-Yáñez ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Rat Model ◽  
Molecular Mechanisms ◽  
Body Weight Gain ◽  
Liver Steatosis ◽  
Phosphorylated Akt ◽  
Sucrose Diet ◽  
High Sucrose Diet ◽  
High Sucrose

Objective: We assessed the sex-specific differences in the molecular mechanisms of insulin resistance in muscle and adipose tissue, in a MS rat model induced by a high sucrose diet. Methods: Male, female, and ovariectomized female Wistar rats were randomly distributed in control and high-sucrose diet (HSD) groups, supplemented for 24 weeks with 20% sucrose in the drinking water. At the end, we assessed parameters related to MS, analyzing the effects of the HSD on critical nodes of the insulin signaling pathway in muscle and adipose tissue. Results: At the end of the treatment, HSD groups of both sexes developed obesity, with a 15, 33 and 23% of body weight gain in male, female, and OVX groups respectively, compared with controls; mainly related to hypertrophy of peripancreatic and gonadal adipose tissue. They also developed hypertriglyceridemia, and liver steatosis, with the last being worse in the HSD females. Compared to the control groups, HSD rats had higher IL1B and TNFA levels and insulin resistance. HSD females were more intolerant to glucose than HSD males. Our observations suggest that insulin resistance mechanisms include an increase in phosphorylated AKT(S473) form in HSD male and female groups and a decrease in phosphorylated P70S6K1(T389) in the HSD male groups from peripancreatic adipose tissue. While in gonadal adipose tissue the phosphorylated form of AKT decreased in HSD females, but not in HSD males. Finally, HSD groups showed a reduction in p-AKT levels in gastrocnemius muscle. Conclusion: A high-sucrose diet induces MS and insulin resistance with sex-associated differences and in a tissue-specific manner.

Therapeutic Effect of Metformin and Vitamin E Versus Prescriptive Diet in Obese Adolescents with Fatty Liver

2011 ◽  
Vol 81 (6) ◽  
pp. 398-406 ◽  
Author(s):  
Akcam ◽  
Boyaci ◽  
Pirgon ◽  
Kaya ◽  
Uysal ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Vitamin E ◽  
Fatty Liver ◽  
Liver Steatosis ◽  
Tnf Alpha ◽  
Dietary Advice ◽  
Model Assessment ◽  
Fasting Insulin ◽  
Alcoholic Fatty Liver ◽  
Obese Adolescents

Objective: The aim of the study was to determine whether metformin or vitamin E treatment for six months is effective in reducing body weight, blood pressure, and also ameliorating insulin resistance, adiponectin, and tumor necrosis factor (TNF)-alpha in obese adolescents with non-alcoholic fatty liver disease (NAFLD). Methods: Sixty-seven obese adolescents with liver steatosis (age range, 9 - 17 years) were included in the study. The metformin group received an 850-mg dose of metformin daily and the vitamin E group received 400 U vitamin E /daily, in capsule form for 6 months, plus an individually tailored diet, exercise, and behavioral therapy. Results: After 6 months later, there was a significant decline in body mass index, and fasting insulin and homeostatic model assessment (HOMA) values in all three groups. Moreover, in comparingson of changes in HOMA among the groups, the metformin- treated group showed significantly improved metabolic control and insulin sensitivity (HOMA) at the end of the study. There were no significant differences for changes of adiponectin, TNF-alpha, in all three groups after 6 months study. Conclusion: These data suggest that metformin treatment is more effective than dietary advice and vitamin E treatment in reducing insulin resistance, and also in ameliorating metabolic parameters such as fasting insulin and lipid levels, in obese adolescents having NAFLD.

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