scholarly journals Changes in FGF21 Serum Concentrations and Liver mRNA Expression in an Experimental Model of Complete Lipodystrophy and Insulin-Resistant Diabetes

2014 ◽  
pp. 483-490 ◽  
Author(s):  
A. ŠPOLCOVÁ ◽  
M. HOLUBOVÁ ◽  
B. MIKULÁŠKOVÁ ◽  
V. NAGELOVÁ ◽  
A. ŠTOFKOVÁ ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Mrna Expression ◽  
Plasma Levels ◽  
Glucose Transporter ◽  
Liver Fat ◽  
Fibroblast Growth Factor 21 ◽  
Glucose Transporter 1 ◽  
Insulin Resistant

Patients with obesity and type 2 diabetes often display high levels of the anti-diabetic factor fibroblast growth factor-21 (FGF21), suggesting that the overproduction of FGF21 may result from increased adiposity in an attempt by white adipose tissue (WAT) to counteract insulin resistance. However, the production of FGF21 diabetes in the absence of WAT has not been examined. In this study, we investigated the effects of lipodystrophy in A-ZIP F-1 mice on FGF21 production in relation to diabetes. A-ZIP F-1 mice displayed high FGF21 plasma levels resulting from enhanced FGF21 mRNA expression in the liver. Concomitant enhancement of FGF21 receptor (FGFR1) and glucose transporter 1 (GLUT-1) mRNA expression was observed in the muscles of A-ZIP F-1 mice. Furthermore, the activation of hypothalamic NPY and AgRP mRNA expression positively correlated with plasma levels of FGF21 but not active ghrelin. Our study demonstrates that an increased FGF21 plasma level in lipodystrophic A-ZIP F-1 mice results mainly from up-regulated liver production but does not suffice to overcome the lipodystrophy-induced severe type 2-diabetes and insulin resistance in the liver linked to the augmented liver fat deposition.

scholarly journals Type 2 Diabetes Mouse Model: Insights into the Contribution of Metabolic Defects to Neurocognitive Decline

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Alexa Loncharich ◽  
Austin Reilly ◽  
Shijun Yan ◽  
Hongxia Ren
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Glucose Transporter ◽  
Metabolic Diseases ◽  
Neurocognitive Deficits ◽  
Treatment Needs ◽  
Resistant Mouse ◽  
Insulin Resistant ◽  
Metabolic Defects

Background and Hypothesis: Metabolic diseases, including type 2 diabetes (T2D), have become increasingly prevalent and their associated medical costs have skyrocketed. Furthermore, recent epidemiological evidence suggests links between metabolic defects and neurodegenerative diseases, such as Alzheimer’s Disease (AD). The increasing coincidence of AD and T2D, and unmet treatment needs, necessitates research investigating potential shared mechanisms. To study glucose and lipid metabolism defects and neurocognitive deficits, we have generated non-obese insulin resistant mouse models, named GLUT4-mediated Insulin Receptor KnockOut (GIRKO). Insulin-responsive glucose transporter, Glut4, is expressed in muscle, fat, and a subset of neurons in the brain. Our previous publications show that GIRKO mice are highly insulin resistant and insulin sensitive GLUT4 neurons are critical mediators for glucose metabolism. We hypothesize that central insulin resistance in GIRKO mice instigates neurocognitive defects.  Experimental Design: We will measure the neurocognitive function of 3- to 4-month old GIRKO mice using Morris water maze (MWM) test.   Results: GIRKO mice exhibited increased escape latency. Additionally, they spent less time in the target quadrant in the probe trial, in which the platform is removed. GIRKO performed equally compared to control mice in raised platform tests, which demonstrates that motor competencies do not confound our findings.  Conclusion and Potential Impact: GIRKO mice have learning and memory deficits, which illustrates a possible link between neurocognition and metabolism.  Our results support the notion that insulin resistance precedes cognitive decline and necessitates early intervention therapy to treat insulin resistance and protect cognitive function. 

scholarly journals Intramuscular triglyceride synthesis: importance in muscle lipid partitioning in humans

2018 ◽  
Vol 314 (2) ◽  
pp. E152-E164 ◽  
Author(s):  
Bryan C. Bergman ◽  
Leigh Perreault ◽  
Allison Strauss ◽  
Samantha Bacon ◽  
Anna Kerege ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Insulin Sensitivity ◽  
Mrna Expression ◽  
Acute Exercise ◽  
Insulin Resistant ◽  
Lipid Desaturation ◽  
Intramuscular Triglyceride ◽  
Athlete’S Paradox

Intramuscular triglyceride (IMTG) concentration is elevated in insulin-resistant individuals and was once thought to promote insulin resistance. However, endurance-trained athletes have equivalent concentration of IMTG compared with individuals with type 2 diabetes, and have very low risk of diabetes, termed the “athlete’s paradox.” We now know that IMTG synthesis is positively related to insulin sensitivity, but the exact mechanisms for this are unclear. To understand the relationship between IMTG synthesis and insulin sensitivity, we measured IMTG synthesis in obese control subjects, endurance-trained athletes, and individuals with type 2 diabetes during rest, exercise, and recovery. IMTG synthesis rates were positively related to insulin sensitivity, cytosolic accumulation of DAG, and decreased accumulation of C18:0 ceramide and glucosylceramide. Greater rates of IMTG synthesis in athletes were not explained by alterations in FFA concentration, DGAT1 mRNA expression, or protein content. IMTG synthesis during exercise in Ob and T2D indicate utilization as a fuel despite unchanged content, whereas IMTG concentration decreased during exercise in athletes. mRNA expression for genes involved in lipid desaturation and IMTG synthesis were increased after exercise and recovery. Further, in a subset of individuals, exercise decreased cytosolic and membrane di-saturated DAG content, which may help explain insulin sensitization after acute exercise. These data suggest IMTG synthesis rates may influence insulin sensitivity by altering intracellular lipid localization, and decreasing specific ceramide species that promote insulin resistance.

scholarly journals Degradation of IRS1 leads to impaired glucose uptake in adipose tissue of the type 2 diabetes mouse model TALLYHO/Jng

2009 ◽  
Vol 203 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Yun Wang ◽  
Patsy M Nishina ◽  
Jürgen K Naggert
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Glucose Uptake ◽  
Molecular Mechanisms ◽  
Glucose Transporter ◽  
Cytokine Signaling ◽  
Mrna Levels ◽  
Insulin Resistant

The TALLYHO/Jng (TH) mouse strain is a polygenic model for type 2 diabetes (T2D) characterized by moderate obesity, impaired glucose tolerance and uptake, insulin resistance, and hyperinsulinemia. The goal of this study was to elucidate the molecular mechanisms responsible for the reduced glucose uptake and insulin resistance in the adipose tissue of this model. The translocation and localization of glucose transporter 4 (GLUT4) to the adipocyte plasma membrane were impaired in TH mice compared to control C57BL6/J (B6) mice. These defects were associated with decreased GLUT4 protein, reduced phosphatidylinositol 3-kinase activity, and alterations in the phosphorylation status of insulin receptor substrate 1 (IRS1). Activation of c-Jun N-terminal kinase 1/2, which can phosphorylate IRS1 on Ser307, was significantly higher in TH mice compared with B6 controls. IRS1 protein but not mRNA levels was found to be lower in TH mice than controls. Immunoprecipitation with anti-ubiquitin and western blot analysis of IRS1 protein revealed increased total IRS1 ubiquitination in adipose tissue of TH mice. Suppressor of cytokine signaling 1, known to promote IRS1 ubiquitination and subsequent degradation, was found at significantly higher levels in TH mice compared with B6. Immunohistochemistry showed that IRS1 colocalized with the 20S proteasome in proteasomal structures in TH adipocytes, supporting the notion that IRS1 is actively degraded. Our findings suggest that increased IRS1 degradation and subsequent impaired GLUT4 mobilization play a role in the reduced glucose uptake in insulin resistant TH mice. Since low-IRS1 levels are often observed in human T2D, the TH mouse is an attractive model to investigate mechanisms of insulin resistance and explore new treatments.

Efficacy and cardiovascular safety of Thiazolidinediones

2020 ◽  
Vol 15 ◽  
Author(s):  
Raveendran Arkiath Veettil ◽  
Cornelius James Fernandez ◽  
Koshy Jacob
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Cardiovascular Disease ◽  
Glucose Transporter ◽  
Cell Function ◽  
Cardiovascular Safety ◽  
Cardiovascular Outcome Trials ◽  
Glucose Transporter 2 ◽  
Insulin Sensitizers

: Type 2 diabetes mellitus (T2DM) is characterized by a progressive beta cell dysfunction in the setting of peripheral insulin resistance. Insulin resistance in subjects with type 2 diabetes and metabolic syndrome is primarily caused by an ectopic fat accumulation in liver and skeletal muscle. Insulin sensitizers are particularly important in the management of T2DM. Though, thiazolidinediones (TZDs) are principally insulin sensitizers, they possess an ability to preserve pancreatic β-cell function and thereby exhibit durable glycemic control. Cardiovascular outcome trials (CVOTs) have shown that Glucagon-like-peptide 1 receptor agonists (GLP-1 RAs) and sodium glucose transporter-2 inhibitors (SGLT2i) have proven cardiovascular safety. In this era of CVOTs, drugs with proven cardiovascular (CV) safety are often preferred in patients with preexisting cardiovascular disease or at risk of cardiovascular disease. In this review, we will describe the three available drugs belonging to the TZD family, with special emphasis on their efficacy and CV safety.

scholarly journals FRI0052 INFLUENCE OF RHEUMATOID ARTHRITIS ON THE CLINICAL AND BIOLOGICAL PROFILE OF TYPE-2 DIABETES MELLITUS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 601.2-602
Author(s):  
J. Avouac ◽  
M. Elhai ◽  
M. Forien ◽  
J. Sellam ◽  
F. Eymard ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Insulin Requirement ◽  
Multivariate Logistic Regression ◽  
Biological Profile ◽  
Research Support ◽  
Insulin Resistant ◽  
Research Grant

Background:Type-2 diabetes and rheumatoid arthritis (RA) are two chronic diseases characterized by tissue inflammation and insulin resistance. To date, no data have evaluated the influence of RA-induced joint and systemic inflammation on the course of type-2 diabetes.Objectives:To study the impact of RA on type-2 diabetesMethods:Observational, multicenter, cross-sectional usual-care study, including 7 rheumatology centers. This study included over a 24-month period consecutive patients with type-2 diabetes and RA, fulfilling the 2010 ACR / EULAR criteria, and diabetic controls with osteoarthritis (OA). The following data were collected: demographics, disease activity and severity indices, current treatment for RA and diabetes, history and complications of diabetes. A systematic blood test was performed, assessing inflammatory (CRP levels) and metabolic (fasting glycemia and insulin levels, HbA1c) parameters. The HOMA2%B (insulin secretion) and HOMA2%S (tissue insulin sensitivity) indices (HOMA calculator, © Diabetes Trials Unit, University of Oxford) were used to assess insulin resistance. Ra and OA patients were compared using parametric tests after adjusting for age and BMI. A multivariate logistic regression was performed ti identify factors independently associated with insulin resistance.Results:We included 122 RA patients (74% women, mean age 64+/-11 years, mean disease duration 15+/-11 11 years, 75% with positive ACPA antibodies and 64% with erosive disease) and 54 controls with OA. 64% of RA patients were treated with oral corticosteroids <10 mg/day, 65% received methotrexate and 53% received targeted biological therapies.The characteristics of type-2 diabetes in the 54 OA patients corresponded to severe insulin-resistant diabetes: age> 65 years, high BMI> 30 kg/m2, mean HbA1c 7.3%+/-11 1.3%, 30% of insulin requirement, high frequency of other cardiovascular risk factors, macroangiopathy found in almost half of patients and biological criteria of insulin resistance (elevation of HOMA2%B and decrease of HOMA2%S).RA patients with type-2 diabetes had a younger age (64+/-11 years vs. 68+/-12 years, p=0.031) and lower BMI (27.7+/-11 5.5 vs. 31.5+/-11 6.3, p<0.001). These patients also had severe diabetes (HbA1c 7.0%+/-11 1.2%, 29% of insulin requirement, 43% of macroangiopathy) with an insulin resistance profile identical to OA controls. After adjusting for age and BMI, RA patients had a significantly increased insulin secretion compared to OA patients (HOMA2%B: 83.1+/-11 65.2 vs. 49.3+/-11 25.7, p=0.023) as well as a significant reduction of insulin sensitivity (HOMA2%S: 61.1+/-11 31.6 vs. 92.9+/-11 68.1, p=0.016). This insulin resistance was associated with the inflammatory activity of RA, with a negative correlation between the HOMA2%S and the DAS28 (r=-0.28, p=0.027). The multivariate logistic regression confirmed the independent association between the HOMA2%S index and DAS28 (OR: 3.93, 95% CI 1.02-15.06), as well as high blood pressure (OR: 1.29, 95% CI 0.33-1.99 CI).Conclusion:RA patients with type-2 diabetes displayed severe, poorly controlled diabetes, highlighting the burden of comorbidities associated with RA. The clinical-biological profile of diabetic RA patients was severe insulin-resistant diabetes, with a biological profile of insulin resistance linked to the inflammatory activity of the disease. These findings may have therapeutic implications, with the potential targeting of insulin resistance through the treatment of joint and systemic inflammation.Acknowledgments:Société Française de Rhumatologie (research grant)Bristol Myers Squibb (research grant)Disclosure of Interests:Jérôme Avouac Grant/research support from: Pfizer, Bristol Myers Squibb, Consultant of: Sanofi, Bristol Myers Squibb, Abbvie, Boerhinger, Nordic Pharma, Speakers bureau: Sanofi, Bristol Myers Squibb Abbvie, MSD, Pfizer, Nordic Pharma, Muriel ELHAI: None declared, Marine Forien: None declared, Jérémie SELLAM: None declared, Florent Eymard Consultant of: Regenlab, Anna Moltó Grant/research support from: Pfizer, UCB, Consultant of: Abbvie, BMS, MSD, Novartis, Pfizer, UCB, Laure Gossec Grant/research support from: Lilly, Mylan, Pfizer, Sandoz, Consultant of: AbbVie, Amgen, Biogen, Celgene, Janssen, Lilly, Novartis, Pfizer, Sandoz, Sanofi-Aventis, UCB, Frédéric Banal: None declared, Joel Daminano: None declared, Philippe Dieudé: None declared, Yannick Allanore Shareholder of: Sanofi, Roche, Consultant of: Actelion, Bayer, BMS, Boehringer Ingelheim, Inventiva, Sanofi

Liver steatosis coexists with myocardial insulin resistance and coronary dysfunction in patients with type 2 diabetes

2006 ◽  
Vol 291 (2) ◽  
pp. E282-E290 ◽  
Author(s):  
Riikka Lautamäki ◽  
Ronald Borra ◽  
Patricia Iozzo ◽  
Markku Komu ◽  
Terho Lehtimäki ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Liver Steatosis ◽  
Fat Content ◽  
Liver Fat ◽  
Liver Fat Content ◽  
Artery Disease ◽  
Myocardial Insulin Resistance ◽  
High Liver

Nonalcoholic fatty liver (NAFL) is a common comorbidity in patients with type 2 diabetes and links to the risk of coronary syndromes. The aim was to determine the manifestations of metabolic syndrome in different organs in patients with liver steatosis. We studied 55 type 2 diabetic patients with coronary artery disease using positron emission tomography. Myocardial perfusion was measured with [15O]H2O and myocardial and skeletal muscle glucose uptake with 2-deoxy-2-[18F]fluoro-d-glucose during hyperinsulinemic euglycemia. Liver fat content was determined by magnetic resonance proton spectroscopy. Patients were divided on the basis of their median (8%) into two groups with low (4.6 ± 2.0%) and high (17.4 ± 8.0%) liver fat content. The groups were well matched for age, BMI, and fasting plasma glucose. In addition to insulin resistance at the whole body level ( P = 0.012) and muscle ( P = 0.002), the high liver fat group had lower insulin-stimulated myocardial glucose uptake ( P = 0.040) and glucose extraction rate ( P = 0.0006) compared with the low liver fat group. In multiple regression analysis, liver fat content was the most significant explanatory variable for myocardial insulin resistance. In addition, the high liver fat group had increased concentrations of high sensitivity C-reactive protein, soluble forms of E-selectin, vascular adhesion protein-1, and intercellular adhesion molecule-1 ( P < 0.05) and lower coronary flow reserve ( P = 0.02) compared with the low liver fat group. In conclusion, in patients with type 2 diabetes and coronary artery disease, liver fat content is a novel independent indicator of myocardial insulin resistance and reduced coronary functional capacity. Further studies will reveal the effect of hepatic fat reduction on myocardial metabolism and coronary function.

Association of glucose transporter 1 polymorphisms with type 2 diabetes in the Tunisian population

2008 ◽  
Vol 24 (7) ◽  
pp. 544-548 ◽  
Author(s):  
K. Makni ◽  
F. Mnif ◽  
M. Boudawara ◽  
N. Hamza ◽  
N. Rekik ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Glucose Transporter ◽  
Tunisian Population ◽  
Glucose Transporter 1

Lipid-Induced Insulin Resistance Mechanisms: The Link to Inflammation and Type 2 Diabetes.

2021 ◽  
pp. 1-9
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Fatty Acid ◽  
Molecular Mechanisms ◽  
Laboratory Data ◽  
Phosphatidyl Inositol ◽  
Resistance Mechanisms ◽  
Cellular Mechanisms ◽  
Insulin Resistant

1. Abstract Insulin Resistance is the leading cause of Type 2 diabetes mellitus [T2DM] onset. It occurs as a result of disturbances in lipid metabolism and increased levels of circulating free fatty acids [FFAs]. FFAs accumulate within the insulin sensitive tissues such as muscle, liver and adipose tissues exacerbating different molecular mechanisms. Increased fatty acid flux has been documented to be strongly associated with insulin resistant states and obesity causing inflammation that eventually causes type 2-diabetes development. FFAs appear to cause this defect in glucose transport by inhibiting insulin –stimulated tyrosine phosphorylation of insulin receptor substrate-1 [IRS-1] and IRS-1 associated phosphatidyl-inositol 3-kinase activity. A number of different metabolic abnormalities may increase intramyocellular or intrahepatic fatty acid metabolites that induce insulin resistance through different cellular mechanisms. The current review point out the link between enhanced FFAs flux and activation of PKC and how it impacts on both the insulin signaling in muscle and liver as shown from our laboratory data and highlighting the involvement of the inflammatory pathways importance. This embarks the importance of measuring the inflammatory biomarkers in clinical settings.

IL-6 as a Surrogate Biomarker: The IL-6 Clinical Value for the Diagnosis of Insulin Resistance and Type 2 Diabetes.

2021 ◽  
pp. 1-13
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Molecular Mechanisms ◽  
Diagnostic Value ◽  
Low Grade ◽  
Clinical Value ◽  
Insulin Resistant ◽  
Tnf Α ◽  
Low Grade Inflammation

1. Abstract Insulin Resistance is the leading cause of Type 2 diabetes mellitus (T2D). It occurs as a result of lipid disorders and increased levels of circulating free fatty acids (FFAs). FFAs accumulate within the insulin sensitive tissues such as muscle, liver and adipose tissues exacerbating different molecular mechanisms. Increased levels fatty acid has been documented to be strongly associated with insulin resistant states and obesity causing inflammation that eventually causes type 2-diabetes. Among the biomarkers that are accompanying low grade inflammation include IL-1β, IL-6 and TNF-α. The current review point out the importance of measuring the inflammatory biomarkers especially focusing on the conductance and measurement for IL-6 as a screening laboratory test and its diagnostic value in clinical practice.

scholarly journals Transient Silencing of a Type IV P-Type ATPase,Atp10c, Results in Decreased Glucose Uptake in C2C12 Myotubes

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
S. E. Hurst ◽  
S. C. Minkin ◽  
J. Biggerstaff ◽  
M. S. Dhar
Keyword(s):  
Type 2 Diabetes ◽  
Glucose Uptake ◽  
Glucose Transporter ◽  
Mapk Pathway ◽  
Specific Inhibitor ◽  
C2c12 Myotubes ◽  
Glucose Transporter 1 ◽  
Transfected Cells

Atp10cis a strong candidate gene for diet-induced obesity and type 2 diabetes. To identify molecular and cellular targets of ATP10C,Atp10cexpression was alteredin vitroin C2C12 skeletal muscle myotubes by transient transfection with anAtp10c-specific siRNA. Glucose uptake assays revealed that insulin stimulation caused a significant 2.54-fold decrease in 2-deoxyglucose uptake in transfected cells coupled with a significant upregulation of native mitogen-activated protein kinases (MAPKs), p38, and p44/42. Additionally, glucose transporter-1 (GLUT1) was significantly upregulated; no changes in glucose transporter-4 (GLUT4) expression were observed. The involvement of MAPKs was confirmed using the specific inhibitor SB203580, which downregulated the expression of native and phosphorylated MAPK proteins in transfected cells without any changes in insulin-stimulated glucose uptake. Results indicate thatAtp10cregulates glucose metabolism, at least in part via the MAPK pathway, and, thus, plays a significant role in the development of insulin resistance and type 2 diabetes.

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