Dysfunction of human subcutaneous fat arterioles in obesity alone or obesity associated with Type 2 diabetes

2011 ◽  
Vol 120 (10) ◽  
pp. 463-472 ◽  
Author(s):  
Adriana Georgescu ◽  
Doina Popov ◽  
Anamaria Constantin ◽  
Miruna Nemecz ◽  
Nicoleta Alexandru ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Protein Expression ◽  
Insulin Signalling ◽  
Subcutaneous Fat ◽  
Signalling Pathway ◽  
Internal Diameter ◽  
No Production ◽  
Insulin Signalling Pathway

The aim of the present study was to examine the effects of obesity alone and obesity associated with Type 2 diabetes on the structure, vascular reactivity and response to insulin of isolated human subcutaneous fat arterioles; these effects were correlated with the expression of insulin signalling proteins. Periumbilical subcutaneous adipose tissue was explanted during surgery, small arterioles (internal diameter 220±40 μm) were dissected out and investigated by electron microscopy, myography and immunoblotting. Compared with the subcutaneous arterioles of lean subjects, obesity activated the endothelium, enhanced the accumulation of collagen within vascular wall and increased the sensitivity of adrenergic response; obesity also diminished eNOS (endothelial NO synthase) protein expression, NO production, and endothelium-dependent and insulin-induced vasodilatation, as well as the protein expression of both IRS (insulin receptor substrates)-1 and IRS-2 and of the downstream molecules in the insulin signalling pathway, such as PI3K (phosphoinositide 3-kinase), phospho-Akt and Akt. When obesity was associated with Type 2 diabetes, these changes were significantly augmented. In conclusion, obesity alone or obesity associated with Type 2 diabetes alters human periumbilical adipose tissue arterioles in terms of structure, function and biochemsitry, including diminished eNOS expression and reduced levels of IRS-1, IRS-2, PI3K and Akt in the insulin signalling pathway.

Effect of food restriction on the insulin signalling pathway in rat skeletal muscle and adipose tissue

2005 ◽  
Vol 16 (10) ◽  
pp. 602-609 ◽  
Author(s):  
Ana Alonso ◽  
Yolanda Fernández ◽  
Rebeca Fernández ◽  
Patricia Ordóñez ◽  
María Moreno ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Food Restriction ◽  
Insulin Signalling ◽  
Signalling Pathway ◽  
Rat Skeletal Muscle ◽  
Insulin Signalling Pathway ◽  
Effect Of Food

Lipopolysaccharide activates an innate immune system response in human adipose tissue in obesity and type 2 diabetes

2007 ◽  
Vol 292 (3) ◽  
pp. E740-E747 ◽  
Author(s):  
S. J. Creely ◽  
P. G. McTernan ◽  
C. M. Kusminski ◽  
ff. M. Fisher ◽  
N. F. Da Silva ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Protein Expression ◽  
Serum Insulin ◽  
Human Adipose Tissue ◽  
Innate Immune ◽  
System Response ◽  
Low Grade ◽  
Tnf Α

Type 2 diabetes (T2DM) is associated with chronic low-grade inflammation. Adipose tissue (AT) may represent an important site of inflammation. 3T3-L1 studies have demonstrated that lipopolysaccharide (LPS) activates toll-like receptors (TLRs) to cause inflammation. For this study, we 1) examined activation of TLRs and adipocytokines by LPS in human abdominal subcutaneous (AbdSc) adipocytes, 2) examined blockade of NF-κB in human AbdSc adipocytes, 3) examined the innate immune pathway in AbdSc AT from lean, obese, and T2DM subjects, and 4) examined the association of circulating LPS in T2DM subjects. The findings showed that LPS increased TLR-2 protein expression twofold ( P < 0.05). Treatment of AbdSc adipocytes with LPS caused a significant increase in TNF-α and IL-6 secretion (IL-6, Control: 2.7 ± 0.5 vs. LPS: 4.8 ± 0.3 ng/ml; P < 0.001; TNF-α, Control: 1.0 ± 0.83 vs. LPS: 32.8 ± 6.23 pg/ml; P < 0.001). NF-κB inhibitor reduced IL-6 in AbdSc adipocytes (Control: 2.7 ± 0.5 vs. NF-κB inhibitor: 2.1 ± 0.4 ng/ml; P < 0.001). AbdSc AT protein expression for TLR-2, MyD88, TRAF6, and NF-κB was increased in T2DM patients ( P < 0.05), and TLR-2, TRAF-6, and NF-κB were increased in LPS-treated adipocytes ( P < 0.05). Circulating LPS was 76% higher in T2DM subjects compared with matched controls. LPS correlated with insulin in controls ( r = 0.678, P < 0.0001). Rosiglitazone (RSG) significantly reduced both fasting serum insulin levels (reduced by 51%, P = 0.0395) and serum LPS (reduced by 35%, P = 0.0139) in a subgroup of previously untreated T2DM patients. In summary, our results suggest that T2DM is associated with increased endotoxemia, with AT able to initiate an innate immune response. Thus, increased adiposity may increase proinflammatory cytokines and therefore contribute to the pathogenic risk of T2DM.

scholarly journals Effect of Food Restriction on Adipose Tissue in Spontaneously Diabetic Torii Fatty Rats

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Hisayo Morinaga ◽  
Takeshi Ohta ◽  
Kenichi Matsui ◽  
Tomohiko Sasase ◽  
Sumiaki Fukuda ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Food Restriction ◽  
Glucose Oxidation ◽  
Subcutaneous Fat ◽  
Epididymal Fat ◽  
Mesenteric Fat ◽  
Effect Of Food ◽  
Novel Drug

Spontaneously Diabetic Torii-fa/fa(SDT fatty) rat is a new model of obese type 2 diabetes. SDT fatty rat exhibits obesity associated with hyperphagia. In this study, SDT fatty rats were subjected to pair-feeding with SDT-+/+ (SDT) rats from 6 to 22 weeks of age. The ratio of visceral fat weight to subcutaneous fat weight (V/S) decreased at 12 weeks of age in the pair-feeding rats. The intraperitoneal fat weight such as epididymal and retroperitoneal fat weight decreased, whereas mesenteric fat weight had no change. Cell size of the epididymal fat in the pair-feeding rats tended to decrease. Glucose oxidation level in epididymal fat in the pair-feeding rats at 12 weeks of age was recovered to a similar level with that in SDT rats. These results indicated that SDT fatty rat is a useful model to evaluate the functional or the morphological features in adipose tissue and develop a novel drug for antiobesity.

The effect of aging on insulin signalling pathway is tissue dependent: Central role of adipose tissue in the insulin resistance of aging

2009 ◽  
Vol 130 (3) ◽  
pp. 189-197 ◽  
Author(s):  
Rosario Serrano ◽  
Margarita Villar ◽  
Nilda Gallardo ◽  
José M. Carrascosa ◽  
Carmen Martinez ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Insulin Signalling ◽  
Signalling Pathway ◽  
Insulin Signalling Pathway

scholarly journals Decreased Thioredoxin-1 and Increased HSP90 Expression in Skeletal Muscle in Subjects with Type 2 Diabetes or Impaired Glucose Tolerance

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
M. Venojärvi ◽  
A. Korkmaz ◽  
S. Aunola ◽  
K. Hällsten ◽  
K. Virtanen ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Glucose Tolerance ◽  
Impaired Glucose Tolerance ◽  
Insulin Signalling ◽  
Vastus Lateralis ◽  
Diabetes Research ◽  
Insulin Signalling Pathway ◽  
Thioredoxin 1

In diabetes, the endogenous defence systems are overwhelmed, causing various types of stress in tissues. In this study, newly diagnosed or diet-treated type 2 diabetics (T2D) (n=10) were compared with subjects with impaired glucose tolerance (IGT) (n=8). In both groups, at resting conditions, blood samples were drawn for assessing metabolic indices and skeletal muscle samples (m. vastus lateralis) were taken for the measurements of cellular defence markers: thioredoxin-1 (TRX-1) and stress proteins HSP72, HSP90. The protein level of TRX-1 was 36.1% lower (P=0.031) and HSP90 was 380% higher (P<0.001) in the T2D than in the IGT subjects, with no significant changes in HSP72. However, after the adjustment of both analyses with HOMA-IR only HSP90 difference remained significant. In conclusion, level of TRX-1 in skeletal muscle tissue was lower while that of HSP90 was higher in T2D than in IGT subjects. This may impair antioxidant defence and lead to disruptions of protein homoeostasis and redox regulation of cellular defences. Because HSP90 may be involved in sustaining functional insulin signalling pathway in type 2 diabetic muscles and higher HSP90 levels can be a consequence of type 2 diabetes, our results are potentially important for the diabetes research.

scholarly journals Increased Expression of the Innate Immune Receptor TLR10 in Obesity and Type-2 Diabetes: Association with ROS-Mediated Oxidative Stress

2018 ◽  
Vol 45 (2) ◽  
pp. 572-590 ◽  
Author(s):  
Sardar Sindhu ◽  
Nadeem Akhter ◽  
Shihab Kochumon ◽  
Reeby Thomas ◽  
Ajit Wilson ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Protein Expression ◽  
Mapk Signaling ◽  
Innate Immune ◽  
Low Grade ◽  
Sod Activity ◽  
Metabolic Inflammation

Background/Aims: Metabolic diseases such as obesity and type-2 diabetes (T2D) are known to be associated with chronic low-grade inflammation called metabolic inflammation together with an oxidative stress milieu found in the expanding adipose tissue. The innate immune Toll-like receptors (TLR) such as TLR2 and TLR4 have emerged as key players in metabolic inflammation; nonetheless, TLR10 expression in the adipose tissue and its significance in obesity/T2D remain unclear. Methods: TLR10 gene expression was determined in the adipose tissue samples from healthy non-diabetic and T2D individuals, 13 each, using real-time RT-PCR. TLR10 protein expression was determined by immunohistochemistry, confocal microscopy, and flow cytometry. Regarding in vitro studies, THP-1 cells, peripheral blood mononuclear cells (PBMC), or primary monocytes were treated with hydrogen peroxide (H2O2) for induction of reactive oxygen species (ROS)-mediated oxidative stress. Superoxide dismutase (SOD) activity was measured using a commercial kit. Data (mean±SEM) were compared using unpaired student’s t-test and P<0.05 was considered significant. Results: The adipose tissue TLR10 gene/protein expression was found to be significantly upregulated in obesity as well as T2D which correlated with body mass index (BMI). ROS-mediated oxidative stress induced high levels of TLR10 gene/protein expression in monocytic cells and PBMC. In these cells, oxidative stress induced a time-dependent increase in SOD activity. Pre-treatment of cells with anti-oxidants/ROS scavengers diminished the expression of TLR10. ROS-induced TLR10 expression involved the nuclear factor-kappaB (NF-κB)/mitogen activated protein kinase (MAPK) signaling as well as endoplasmic reticulum (ER) stress. H2O2-induced oxidative stress interacted synergistically with palmitate to trigger the expression of TLR10 which associated with enhanced expression of proinflammatory cytokines/chemokine. Conclusion: Oxidative stress induces the expression of TLR10 which may represent an immune marker for metabolic inflammation.

scholarly journals Beneficial effects of dietary restriction in type 2 diabetic rats: the role of adipokines on inflammation and insulin resistance

2010 ◽  
Vol 104 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Joana Crisóstomo ◽  
Lisa Rodrigues ◽  
Paulo Matafome ◽  
Carmen Amaral ◽  
Elsa Nunes ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Dietary Restriction ◽  
Insulin Signalling ◽  
Diabetic Rats ◽  
Energy Restriction ◽  
Beneficial Effects

Inflammation plays an important role in diabetes mellitus and its complications. In this context, the negative cross-talk between adipose tissue and skeletal muscle leads to disturbances in muscle cell insulin signalling and induces insulin resistance. Because several studies have shown that energy restriction brings some benefits to diabetes, the aim of the present study was to evaluate the effects of dietary restriction on systemic and skeletal muscle inflammatory biomarkers, such C-reactive protein, adipokines and cytokines, and in insulin resistance in Goto-Kakizaki rats. This is an animal model of spontaneous non-obese type 2 diabetes with strongly insulin resistance and without dyslipidaemia. Animals were maintained during 2 months of dietary restriction (50 %) and were killed at 6 months of age. Some biochemical determinations were done using ELISA and Western blot. Data from the present study demonstrate that in Goto-Kakizaki rats the dietary restriction improved insulin resistance, NEFA levels and adipokine profile and ameliorated inflammatory cytokines in skeletal muscle. These results indicate that dietary restriction in type 2 diabetes enhances adipose tissue metabolism leading to an improved skeletal muscle insulin sensitivity.

scholarly journals MECHANISMS IN ENDOCRINOLOGY: Metabolic and inflammatory pathways on the pathogenesis of type 2 diabetes

2016 ◽  
Vol 174 (5) ◽  
pp. R175-R187 ◽  
Author(s):  
Andressa Coope ◽  
Adriana S Torsoni ◽  
Licio A Velloso
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Insulin Signalling ◽  
Inflammatory Factors ◽  
Main Risk Factor ◽  
Metabolic Inflammation ◽  
Insulin Signalling Pathway

Obesity is the main risk factor for type 2 diabetes (T2D). Studies performed over the last 20 years have identified inflammation as the most important link between these two diseases. During the development of obesity, there is activation of subclinical inflammatory activity in tissues involved in metabolism and energy homeostasis. Intracellular serine/threonine kinases activated in response to inflammatory factors can catalyse the inhibitory phosphorylation of key proteins of the insulin-signalling pathway, leading to insulin resistance. Moreover, during the progression of obesity and insulin resistance, the pancreatic islets are also affected by inflammation, contributing to β-cell failure and leading to the onset of T2D. In this review, we will present the main mechanisms involved in the activation of obesity-associated metabolic inflammation and discuss potential therapeutic opportunities that can be developed to treat obesity-associated metabolic diseases.

scholarly journals Diabetes and obesity during pregnancy alter insulin signalling and glucose transporter expression in maternal skeletal muscle and subcutaneous adipose tissue

2009 ◽  
Vol 44 (4) ◽  
pp. 213-223 ◽  
Author(s):  
Michelle Colomiere ◽  
Michael Permezel ◽  
Martha Lappas
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Glucose Transporter ◽  
Insulin Signalling ◽  
Signalling Pathway ◽  
Glut 1 ◽  
Glut 4 ◽  
Insulin Signalling Pathway ◽  
Subcutaneous Adipose ◽  
Diabetes And Obesity

Severe insulin resistance is a defining attribute of gestational diabetes mellitus (GDM). It is postulated that alterations in the insulin-signalling pathway and subsequent glucose disposal are the underlying cause of insulin resistance in patients with GDM. The purpose of this study was to profile the insulin-signalling pathway and intermediates in insulin-sensitive tissues. Subcutaneous adipose tissue and skeletal muscle were collected from normal glucose-tolerant (NGT) and insulin-controlled GDM in both non-obese and obese cohorts (n=6–8 per subgroup). Expression studies of the insulin-signalling pathway were performed using western blotting and quantitative reverse transcription-PCR. This study demonstrated altered mRNA expression of insulin receptor substrate (IRS)-1, IRS-2, glucose transporter (GLUT)-1, GLUT-4 and glycogen synthase kinase (GSK)-3 isoforms genes in adipose tissue in GDM women in comparison to NGT pregnant controls. In skeletal muscle, insulin-controlled GDM was associated with decreased IRS-1, phosphatidylinositol-3-kinase (PI3-K) p85α, GLUT-1 and -4, GSK-3 isoforms and phosphoinositide-dependent kinase-1. Both adipose tissue and skeletal muscle from women with GDM displayed decreased IRS-1 and GLUT-4 and increased PI3-K p85α protein expression. Both skeletal muscle and adipose tissue from obese women demonstrated lower GLUT-1 and -4 mRNA expression and diminished GLUT-4 protein expression in skeletal muscle only. Collectively, our results suggest that diabetes and obesity during pregnancy cause defects in insulin-signalling transduction in adipose tissue and skeletal muscle and may be the underlying cause of GDM.

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