Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Current research suggests that insulin resistance is associated with endothelial dysfunction, which is considered an early but significant step in the pathogenesis of atherosclerosis. Both insulin resistance and endothelial dysfunction appear to precede the development of overt hyperglycemia in patients with type 2 diabetes. Therefore, in patients with diabetes or insulin resistance, endothelial dysfunction may be a critical early target for preventing atherosclerosis and cardiovascular disease. Insulin-sensitizing agents--specifically, thiazolidinediones (TZDs)--may be useful for preventing or mitigating endothelial dysfunction. In vitro and clinical data show that TZDs can limit thrombotic, inflammatory, and oxidative changes that contribute to endothelial dysfunction. For example, TZDs have been shown to lower blood levels of plasminogen activator inhibitor-1, a prothrombotic substance, in patients with diabetes or insulin resistance. In obese patients, TZD treatment can improve vascular reactivity and reduce monocyte expression of nuclear factor kappa-B, a transcription factor that contributes to inflammation and oxidative damage. In patients with overt diabetes or insulin resistance, TZD treatment can lower blood levels of C-reactive protein and interleukin-6, markers of inflammation and cardiovascular risk. These beneficial effects of TZDs may help to decrease the risk of vascular damage and atherosclerosis in patients with insulin resistance or diabetes.
 ...
PMID:Insulin resistance and endothelial dysfunction in atherosclerosis: implications and interventions. 1261 87

Visceral adipose tissue (VAT) imaged by computed tomography (CT) or magnetic resonance imaging (MRI) is associated with the metabolic syndrome features, being morphologically and functionally different from subcutaneous adipose tissue (SAT). Insulin effect is lower and catecholamine effect higher in visceral adipose tissue, with its metabolites and its secretions draining through portal system, partially at least, to the liver. Thus, visceral cells transfer and release fatty acids more extensively, have increased glucocorticoid and reduced thiazolidinedione responses, produce more angiotensinogen, interleukin-6 and plasminogen activator inhibitor-1, and secrete less leptin and adiponectin than SAT. Furthermore, there are regional differences in the intrinsic characteristics of the preadipocytes, with those of SAT presenting greater differentiation and fat cell gene expression but less apoptosis than that of VAT. All features contribute to the morbidity associated with increased VAT. To evaluate the relationship between VAT and components of the metabolic syndrome, 55 non-diabetic women, 11 lean (VAT < 68 cm 2) and 44 obese were studied. The obese with VAT within the normal range (VAT < or = 68 cm 2) had higher BMI, WHR, BP and resistance to FFA suppression during oGTT in comparison to the lean controls. The obese with VAT > 68 cm 2 compared to those with VAT < or = 68 cm 2 had similar body mass index (BMI) but significantly higher in vivo homeostasis model assessment for insulin resistance (HOMA IR ) results and triglycerides. By pooling all data, correlation analysis indicated that VAT contributes more to insulin resistance (HOMA IR ) than SAT does, but not when insulin-suppressed plasma free fatty acids during oral glucose tolerance test as an index of insulin resistance are taken into consideration.
 ...
PMID:Depot-specific hormonal characteristics of subcutaneous and visceral adipose tissue and their relation to the metabolic syndrome. 1266 Aug 70

High circulating levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) are found in patients with hyperinsulinemia. Insulin stimulates release of IL-6 from adipocyte cultures, and it stimulates IL-6 gene expression in insulin-resistant, but not control, rat skeletal muscle. In addition, TNF-alpha may be involved in the pathogenesis of insulin resistance. Therefore, we studied the effect of insulin on IL-6 and TNF-alpha gene expression in human skeletal muscle and adipose tissue. Nine healthy young volunteers participated in the study. They underwent a 6-h hyperinsulinemic euglycemic clamp at a fixed insulin infusion rate, with blood glucose clamped at fasting level. Blood samples drawn at 0, 1, 2, 3, 4, 5, and 6 h were analyzed for IL-6 and TNF-alpha. Muscle and fat biopsies, obtained at 0, 2, 4, and 6 h, were analyzed for IL-6 and TNF-alpha mRNA with real-time PCR. IL-6 mRNA increased 11-, 3-, and 5-fold at 2, 4, and 6 h, respectively, in adipose tissue (ANOVA P = 0.027), whereas there was no significant effect of insulin on skeletal muscles. Plasma IL-6 increased during insulin stimulation. TNF-alpha mRNA increased 2.4-, 1.4-, and 2.2-fold in adipose tissue (ANOVA P = 0.001) and decreased 0.74-, 0.64-, and 0.68-fold in muscle tissue (ANOVA P = 0.04). Plasma levels of TNF-alpha were constant. In conclusion, the finding that insulin stimulates IL-6 and TNF-alpha gene expression in adipose tissue only and inhibits the TNF-alpha production in skeletal muscles suggests a differential regulation of muscle- and adipose tissue-derived IL-6 and TNF-alpha.
 ...
PMID:Insulin stimulates interleukin-6 and tumor necrosis factor-alpha gene expression in human subcutaneous adipose tissue. 1453 68

Insulin resistance, both in nondiabetic and diabetic subjects, is frequently associated with obesity, particularly an excess of central fat. Many of the features that have been ascribed to the metabolic or insulin-resistance syndrome are also more commonly found in obese subjects. These phenotypes include diabetic dyslipidaemia, elevation of levels of plasminogen activator inhibitor-1, microalbuminuria and endothelial dysfunction. More recently, features of acute-phase activation and low-grade inflammation, including elevated levels of fibrinogen, C-reactive protein and interleukin-6, have been associated with (central) obesity. Adipose tissue generation of cytokines has been shown in vitro and in vivo, and a number of novel cytokine-like molecules, collectively termed adipocytokines, have been identified as adipocyte products. While several of these, such as tumour necrosis factor-alpha, may act predominantly in autocrine or paracrine fashion, others are released into the systemic circulation, acting as signalling molecules to remote tissues, including liver, skeletal muscle and endothelium. A clearer understanding of adipose tissue signalling, and its contribution to the state of low-grade inflammation of obesity, will require physiological, as well as cellular and molecular, studies.
 ...
PMID:Adipose tissue, insulin action and vascular disease: inflammatory signals. 1470 40

Circulating interleukin-6 (IL-6), insulin, and free fatty acid (FFA) concentrations are associated with impaired insulin action in obese and type 2 diabetic individuals. However, a causal relationship between elevated plasma FFAs and IL-6 has not been shown. Because skeletal muscle represents a major target of impaired insulin action, we studied whether FFAs may affect IL-6 expression in human myotubes. We demonstrate that specifically saturated FFAs, e.g. palmitate (0.25 mm), induce IL-6 mRNA expression and protein secretion by a proteasome-dependent mechanism that leads to a rapid and chronic activation of nuclear factor-kappaB. Insulin, high glucose concentrations, or unsaturated FFAs did not activate IL-6 expression. In fact, the unsaturated FFA linoleate inhibited palmitate-induced IL-6 production. Because inhibition of palmitate metabolism by the acyl-CoA synthetase inhibitor triacsin C did not abolish IL-6 expression, it appears that the palmitate molecule per se exerts the observed effects. Furthermore, we show that in human myotubes, IL-6 activates the phosphorylation of signal transducer and activator of transcription 3 in concentrations similar to hepatocytes. However, no inhibitory effect of IL-6 on insulin action, determined as phosphatidylinositol 3-kinase association with insulin receptor substrate-1, Akt phosphorylation, and glycogen synthesis, was detected. We conclude that IL-6 expression may be modulated by the composition of circulating FFA, e.g. by diet, and that skeletal muscle cells could be target cells for IL-6.
 ...
PMID:Palmitate, but not unsaturated fatty acids, induces the expression of interleukin-6 in human myotubes through proteasome-dependent activation of nuclear factor-kappaB. 1502 33

The aim of this study was to determine the respective contribution of abdominal visceral adipose tissue (AT) accumulation and insulin resistance (IR) to the determination of a comprehensive cardiovascular metabolic risk profile in 108 postmenopausal women not receiving hormone therapy. Insulin sensitivity (M/I) was determined by a hyperinsulinemic-euglycemic clamp, and visceral AT area was measured by computed tomography. Median values of visceral AT (133.9 cm(2)) and insulin sensitivity (0.010189 mg . kg(-1) . min(-1) . pmol(-1)) were used to form four subgroups: 1) low visceral AT-low IR (n = 35), 2) low visceral AT-high IR (n = 19), 3) high visceral AT-low IR (n = 19), and 4) high visceral AT-high IR (n = 35). Women with isolated IR (low visceral AT and high IR) were characterized by significantly higher fasting and 2-h glycemia and higher fibrinogen, triglyceride, and VLDL-apolipoprotein (apo)B concentrations than women with low visceral AT and low IR (P < 0.05). The plasma lipid-lipoprotein profile and inflammatory markers were not significantly different between women with high visceral AT and low IR and women with low visceral AT and low IR. Women with high visceral AT and high IR had higher fasting and 2-h glycemia, triglyceride, and VLDL-apoB levels; lower apoAI and HDL(2) cholesterol levels; as well as higher C-reactive protein and interleukin-6 concentrations than women with low visceral AT and low IR (P < 0.05). In addition, 15 of the 35 women (42.9%) in the high visceral AT and high IR group were newly diagnosed with type 2 diabetes, whereas no women were diagnosed with type 2 diabetes in the group of women with low visceral AT and low IR. These results show that although the presence of high IR in its isolated form is associated with some metabolic alterations, it is the combination of both high visceral AT and high IR that is the most detrimental for the metabolic health in postmenopausal women.
 ...
PMID:Contribution of abdominal visceral obesity and insulin resistance to the cardiovascular risk profile of postmenopausal women. 1573 55

Diabetic heart failure may be causally associated with alterations in cardiac energy metabolism and insulin resistance. Mice with heart-specific overexpression of peroxisome proliferator-activated receptor (PPAR)alpha showed a metabolic and cardiomyopathic phenotype similar to the diabetic heart, and we determined tissue-specific glucose metabolism and insulin action in vivo during hyperinsulinemic-euglycemic clamps in awake myosin heavy chain (MHC)-PPARalpha mice (12-14 weeks of age). Basal and insulin-stimulated glucose uptake in heart was significantly reduced in the MHC-PPARalpha mice, and cardiac insulin resistance was mostly attributed to defects in insulin-stimulated activities of insulin receptor substrate (IRS)-1-associated phosphatidylinositol (PI) 3-kinase, Akt, and tyrosine phosphorylation of signal transducer and activator of transcription 3 (STAT3). Interestingly, MHC-PPARalpha mice developed hepatic insulin resistance associated with defects in insulin-mediated IRS-2-associated PI 3-kinase activity, increased hepatic triglyceride, and circulating interleukin-6 levels. To determine the underlying mechanism, insulin clamps were conducted in 8-week-old MHC-PPARalpha mice. Insulin-stimulated cardiac glucose uptake was similarly reduced in 8-week-old MHC-PPARalpha mice without changes in cardiac function and hepatic insulin action compared with the age-matched wild-type littermates. Overall, these findings indicate that increased activity of PPARalpha, as occurs in the diabetic heart, leads to cardiac insulin resistance associated with defects in insulin signaling and STAT3 activity, subsequently leading to reduced cardiac function. Additionally, age-associated hepatic insulin resistance develops in MHC-PPARalpha mice that may be due to altered cardiac metabolism, functions, and/or inflammatory cytokines.
 ...
PMID:Cardiac-specific overexpression of peroxisome proliferator-activated receptor-alpha causes insulin resistance in heart and liver. 1612 38

The production of inflammatory mediators by abdominal adipose tissue may link obesity and insulin resistance. We determined the influence of systemic levels of interleukin-6 and C-reactive protein on insulin sensitivity after weight loss via Roux-en-Y gastric bypass surgery. Severely obese individuals (n = 15) were evaluated at baseline and at 6 months after surgery. Insulin sensitivity was determined by frequently sampled intravenous glucose tolerance testing at the same time points. Visceral and subcutaneous adipose tissue volumes were quantified by computed tomography. Interleukin-6 and C-reactive protein were measured by enzyme-linked immunoassay in plasma and in adipose tissue biopsies. Correlation analysis was used to determine associations between insulin sensitivity and other outcome variables. Significance was set at P < 0.05. Plasma interleukin-6 concentrations were significantly correlated to the IL-6 content of subcutaneous adipose tissue (r = 0.71). At 6 months postsurgery, subcutaneous and visceral adipose tissue volumes were significantly reduced (34.7% and 44.1%, respectively) and insulin sensitivity had improved by 160.9%. Significant longitudinal correlations were found between insulin sensitivity and plasma C-reactive protein (r = -0.61), but not plasma interleukin-6 at 6 months. These findings offer insights that link obesity and insulin resistance via the activity of inflammatory mediators.
 ...
PMID:Changes in C-reactive protein predict insulin sensitivity in severely obese individuals after weight loss surgery. 1626 83

Thiazolidinedione (TZD) compounds enhance insulin sensitivity and attenuate inflammation. The effect of the TZD compound, rosiglitazone (RSG) on both actions was evaluated in two groups of insulin-resistant subjects with minimal elevations of fasting plasma glucose (PG) concentration: group A (n=15, PG < 7.0 mmol/L) and group B (n=14, PG 7.0-8.3 mmol/L). Insulin action, quantified by the insulin suppression test, improved after three months of treatment in both groups, and concentrations of C-reactive protein, plasminogen activator inhibitor-1 and Eselectin all fell. Significant decreases in L-selectin and P-selectin were confined to group B, and concentrations of interleukin-6, intercellular adhesion molecule-1 and vascular cellular adhesion molecule-1 did not fall in either group. Significant relationships were not discerned between enhanced insulin sensitivity and related variables and decreases in inflammatory/vascular markers, suggesting that RSG-induced changes in the latter variables in insulin-resistant individuals might be at least partly independent of the effects of the drug on insulin action.
 ...
PMID:Effect of rosiglitazone treatment on circulating vascular and inflammatory markers in insulin-resistant subjects. 1630 71

In addition to serving as an energy reservoir, the adipocyte has been characterized as an endocrine cell, secreting many bioactive factors which influence energy homeostasis. Being overweight, with excessive adipose tissue, is considered to be part of the pathogenesis of type 2 diabetes. Insulin resistance and beta-cell dysfunction are two major pathophysiological changes seen in type 2 diabetes. In addition to inducing insulin resistance in insulin-responsive tissues, adipocyte-derived factors play an important role in the pathogenesis of beta-cell dysfunction. Leptin, free fatty acids, adiponectin, tumor necrosis factor-alpha and interleukin-6 are all produced and secreted by adipocytes, and may directly influence aspects of beta-cell function, including insulin synthesis and secretion, insulin cell survival and apoptosis. During the progression from normal weight to obesity and on to overt diabetes, the adipocyte-derived factors contribute to the occurrence and development of beta-cell dysfunction and type 2 diabetes.
 ...
PMID:Contribution of adipocyte-derived factors to beta-cell dysfunction in diabetes. 1637 47


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>