Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011860 (type 2 diabetes)
 57,723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

TNF-alpha is considered as one of the potential determinants of insulin resistance. However several data suggest that TNF-alpha expression itself, could be modulated by the degree of adiposity and/or plasma insulin levels. To clarify the determinants of plasma TNF-alpha levels in type 2 diabetes mellitus, we studied the impact of intensive insulin treatment on plasma TNF-alpha levels in 16 type 2 diabetic subjects with failure to oral antidiabetic medication (HbA1c: 10.8 +/- 1.2 %). Furthermore, we analyzed the relationship between plasma TNF-alpha levels and total or regional body fat measurements using anthropometry, bienergetic absorptiometry and computed tomography in a cohort of 33 caucasian obese type 2 diabetic subjects (BMI: 32.2 +/- 4.4 kg/m(2) ). The plasma TNF-alpha level was neither affected by plasma glucose level variations nor intensive insulin treatment despite a 37 % decrease in daily insulin needs at the end of insulin therapy (total duration: 11.5 +/- 2.0 days). The plasma TNF-alpha level was similar in men and women and unrelated to age, fasting glycemia or HbA1c. A relationship was highlighted with BMI (r =0.39, p <0.02), but not with total fat mass. This relationship was only dependent on the intra-abdominal fat mass amount as assessed by the waist-to-hip circumference ratio (r =0.52, p <0.01) and the visceral adipose tissue area (r =0.56, p <0. 01). These results show that plasma TNF-alpha levels are essentially dependent on visceral fat amount, thus suggesting that TNF-alpha could be one of the factors mediating insulin resistance and cardiovascular risk in obese type 2 diabetic patients.
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PMID:Plasma levels of tumor necrosis factor-alpha (TNF-alpha) are essentially dependent on visceral fat amount in type 2 diabetic patients. 1088 Aug 90

The peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor that regulates fat-cell development and glucose homeostasis and is the molecular target of a class of insulin-sensitizing agents used for the management of type 2 diabetes mellitus. PPARgamma is highly expressed in macrophage foam cells of atherosclerotic lesions and has been demonstrated in cultured macrophages to both positively and negatively regulate genes implicated in the development of atherosclerosis. We report here that the PPARgamma-specific agonists rosiglitazone and GW7845 strongly inhibited the development of atherosclerosis in LDL receptor-deficient male mice, despite increased expression of the CD36 scavenger receptor in the arterial wall. The antiatherogenic effect in male mice was correlated with improved insulin sensitivity and decreased tissue expression of TNF-alpha and gelatinase B, indicating both systemic and local actions of PPARgamma. These findings suggest that PPARgamma agonists may exert antiatherogenic effects in diabetic patients and provide impetus for efforts to develop PPARgamma ligands that separate proatherogenic activities from antidiabetic and antiatherogenic activities.
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PMID:Peroxisome proliferator-activated receptor gamma ligands inhibit development of atherosclerosis in LDL receptor-deficient mice. 1097 14

Aging is associated with increased inflammatory activity reflected by increased circulating levels of TNF-alpha, IL-6, cytokine antagonists and acute phase proteins in vivo. Epidemiologic studies suggest that chronic low-grade inflammation in aging promotes an atherogenic profile and is related to age-associated disorders (eg, Alzheimer disease, atherosclerosis, type 2 diabetes, etc.) and enhanced mortality risk. Accordingly, a dysregulated production of inflammatory cytokines has an important role in the process of aging. Studies of age-related differences in the production of proinflammatory cytokines in response to acute stimulations in vitro have yielded inconsistent results. However, in vivo infectious models show delayed termination of inflammatory activity and a prolonged fever response in elderly humans, suggesting that the acute phase response is altered in aging. However, a causal relation between the acute phase response and the increased mortality because of bacterial infections in older patients remains to be demonstrated.
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PMID:Aging and proinflammatory cytokines. 1130 44

Tumor necrosis factor (TNF)-alpha is one of the candidate mediators of insulin resistance associated with obesity, a major risk factor for the development of type 2 diabetes. The insulin resistance induced by TNF-alpha is antagonized by thiazolidinediones (TZDs), a new class of insulin-sensitizing drugs. The aim of the current study was to dissect the mechanism whereby pioglitazone, one of the TZDs, ameliorates TNF-alpha-induced insulin resistance in 3T3-L1 adipocytes. Pioglitazone restored insulin-stimulated 2-deoxyglucose (DOG) uptake, which was reduced by TNF-alpha, with concomitant restorations in tyrosine phosphorylation and protein levels of insulin receptor (IR) and insulin receptor substrate (IRS)-1, as well as association of the p85 regulatory subunit of phosphatidylinositol (PI) 3-kinase with IRS-1 and PI 3-kinase activity. Adenovirus-mediated gene transfer of either wild-type human peroxisome proliferator-activated receptor (PPAR)-gamma2 or a mutant carrying a replacement at the consensus mitogen-activated protein kinase phosphorylation site (hPPAR-gamma2-S112A) promoted adipogenesis of 3T3-L1 fibroblasts and restored TNF-alpha-induced decrease of triglyceride in adipocytes as effectively as pioglitazone. Overexpression of the PPAR-gamma proteins in TNF-alpha-treated adipocytes restored protein levels of IR/IRS-1, but did not improve insulin-stimulated tyrosine phosphorylation of IR/IRS-1 or insulin-stimulated 2-DOG uptake. These results indicate that the ability of pioglitazone to restore insulin-stimulated tyrosine phosphorylation of IR/IRS-1, which is necessary for amelioration of TNF-alpha-induced insulin resistance, may be independent of the adipogenic activity of PPAR-gamma that regulates protein levels of IR/IRS-1.
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PMID:Pioglitazone ameliorates tumor necrosis factor-alpha-induced insulin resistance by a mechanism independent of adipogenic activity of peroxisome proliferator--activated receptor-gamma. 1133 12

Insulin resistance and its dreaded consequence, type 2 diabetes, are major causes of atherosclerosis. Adiponectin is an adipose-specific plasma protein that possesses anti-atherogenic properties, such as the suppression of adhesion molecule expression in vascular endothelial cells and cytokine production from macrophages. Plasma adiponectin concentrations are decreased in obese and type 2 diabetic subjects with insulin resistance. A regimen that normalizes or increases the plasma adiponectin might prevent atherosclerosis in patients with insulin resistance. In this study, we demonstrate the inducing effects of thiazolidinediones (TZDs), which are synthetic PPARgamma ligands, on the expression and secretion of adiponectin in humans and rodents in vivo and in vitro. The administration of TZDs significantly increased the plasma adiponectin concentrations in insulin resistant humans and rodents without affecting their body weight. Adiponectin mRNA expression was normalized or increased by TZDs in the adipose tissues of obese mice. In cultured 3T3-L1 adipocytes, TZD derivatives enhanced the mRNA expression and secretion of adiponectin in a dose- and time-dependent manner. Furthermore, these effects were mediated through the activation of the promoter by the TZDs. On the other hand, TNF-alpha, which is produced more in an insulin-resistant condition, dose-dependently reduced the expression of adiponectin in adipocytes by suppressing its promoter activity. TZDs restored this inhibitory effect by TNF-alpha. TZDs might prevent atherosclerotic vascular disease in insulin-resistant patients by inducing the production of adiponectin through direct effect on its promoter and antagonizing the effect of TNF-alpha on the adiponectin promoter.
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PMID:PPARgamma ligands increase expression and plasma concentrations of adiponectin, an adipose-derived protein. 1152 76

Insulin resistance is associated with hypertension, obesity, dyslipidemia, and type 2 diabetes. It is well known that tumor necrosis factor (TNF)-alpha is one of the factors linked to obesity-induced insulin resistance; however, there have been no reports on the role of TNF-alpha in insulin resistance in nonobese insulin-resistant hypertensives. We tested the hypothesis that TNF-alpha affects insulin resistance in nonobese insulin-resistant hypertensive fructose-fed rats (FFR) and that a TNF-alpha--converting enzyme (TACE) inhibitor that blocks TNF-alpha secretion improves insulin resistance in FFR. Six-week-old male Sprague-Dawley rats were fed either standard chow (control) or fructose-rich chow (FFR) for 6 weeks. For the last two weeks of a six-week period of either diet, the rats were treated with a vehicle (control or FFR) or a TACE inhibitor (100 mg/kg/d of KB-R7785; FFR+TACE-I) in peritoneal injection. At the age of 12 weeks, insulin sensitivity was assessed in all conscious rats by the euglycemic hyperinsulinemic glucose clamp technique. While FFR had higher blood pressure than the control rats (P<0.01), the TACE inhibitor did not change blood pressure. Insulin sensitivity (M-value) was reduced in FFR compared with that in the control rats (16.7 +/- 1.1 mg/kg per min and 10.3 +/- 0.6 mg/kg per min in the control rats and FFR, respectively, P<0.001), and the TACE inhibitor improved insulin sensitivity to the level of the control rats (14.3 +/- 1.2 mg/kg per min in FFR+TACE-I, P<0.01). These data indicate that TNF-alpha plays a major role in insulin resistance in nonobese insulin-resistant models and also suggest that TACE would be a good target for controlling insulin resistance not only in obese models but also in nonobese insulin-resistant models.
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PMID:Effect of TNF-alpha--converting enzyme inhibitor on insulin resistance in fructose-fed rats. 1188 11

Evidence points to an increased cytokine response in type 2 diabetes, especially the proinflammatory cytokines interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha. Genetics, age, and, nutrition are important signals for this increased response and as reported more recently, infections and inflammation. Persistent elevation of IL-1 beta, IL-6, and TNF-alpha in the diabetic state have an effect on the liver, stimulate the release of acute-phase proteins, produce the characteristic dysregulation of lipid metabolism associated with type 2 diabetes, and have effects on pancreatic beta cells as well. In addition, TNF-alpha, a potent inhibitor of the tyrosine kinase activity of the insulin receptor, has been implicated as an etiologic factor for insulin resistance. Collectively, the evidence supports a role for cytokine elevation in the pathophysiology and metabolic abnormalities associated with diabetes. Periodontitis is an infection that is twice as prevalent in diabetic individuals compared to non-diabetics. Porphyromonas gingivalis, one of the microorganisms responsible for this infection, is able to invade endothelial cells and is a potent signal for monocyte and macrophage activation. Thus, once established in the diabetic host, this chronic infection complicates diabetes control and increases the occurrence and severity of microvascular and macrovascular complications. Unlike treatment of acute infections, modalities of treatment for chronic infections are a matter of debate. Evidence indicates that mechanical removal of subgingival infection does not result in complete elimination of periodontal infection and consequently there is no effect on diabetes control measured as reduction in glycated hemoglobin. On the other hand, studies incorporating systemic antibiotics as adjuncts to mechanical debridement result in a reduction of P. gingivalis to nondetectable levels and a concomitant reduction in glycated hemoglobin, independent of the hypoglycemic effects of diabetes drugs or insulin. The evidence supports the notion that treatment of chronic periodontal infection is essential in the diabetic patient. Assessment of infection status in diabetic patients is fundamental for appropriate treatment decisions.
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PMID:Treatment of periodontal disease and control of diabetes: an assessment of the evidence and need for future research. 1188 56

Fatty acid uptake into 3T3 L1 adipocytes is predominantly transporter mediated. Here we show that, during 3T3 L1 adipocyte differentiation, expression of fatty acid transport proteins (FATPs) 1 and 4 is induced. Using subcellular membrane fractionation and immunofluorescence microscopy, we demonstrate that, in adipocytes, insulin induces plasma membrane translocation of FATPs from an intracellular perinuclear compartment to the plasma membrane. This translocation was observed within minutes of insulin treatment and was paralleled by an increase in long chain fatty acid (LCFA) uptake. In contrast, treatment with TNF-alpha inhibited basal and insulin-induced LCFA uptake and reduced FATP1 and -4 levels. Thus, hormonal regulation of FATP activity may play an important role in energy homeostasis and metabolic disorders such as type 2 diabetes.
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PMID:Insulin causes fatty acid transport protein translocation and enhanced fatty acid uptake in adipocytes. 1197 Aug 97

Ample evidence supports a role for tumour necrosis factor alpha (TNFalpha) in the development of type 2 diabetes and cardiovascular disease. TNFalpha expression was found to be influenced by a -308G/A polymorphism in the promoter of the gene encoding TNFalpha (TNF). We investigated the contribution of this polymorphism to diabetes and cardiovascular mortality in a population-based cohort of 664 subjects aged 85 years and over (Leiden 85-plus Study). The -308G/A TNF promoter polymorphism was associated with the prevalence of diabetes in old age (P = 0.006). The risk of diabetes among subjects homozygous for the A-allele was estimated to be 4.6-fold (95% CI, 1.6-13.3) higher than among subjects homozygous for the common G-allele. The promoter polymorphism did not, however, predict mortality from all causes, cardiovascular diseases, cancer or infectious diseases during a 10-year follow-up period. In addition to the promoter polymorphism, TNFa and TNFc microsatellite genotypes were determined but these polymorphisms were not associated with morbidity or mortality. In conclusion, the -308G/A polymorphism in the TNF promoter is strongly associated with the risk of diabetes but not cardiovascular mortality in old age.
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PMID:Association of the tumour necrosis factor alpha -308G/A polymorphism with the risk of diabetes in an elderly population-based cohort. 1205 58

The major risk factor for the development of insulin resistance and type 2 diabetes is obesity. A key role is the new understanding of adipocytes as an endocrine system. Adipocytes secrete numerous substances that contribute to peripheral insulin resistance, including adiponectin, resistin, TNF-alpha and interleukin 6. There is also a role of free fatty acids by blocking directly intracellular metabolism of glucose and by their lipotoxicity. The pre-receptor metabolism of cortisol may be enhanced in visceral adipose tissue by activation of 11 beta-hydroxysteroid dehydrogenase type 1. The new class of thiazolidinediones (glitazones), binding to the peroxisome proliferator activated receptor (PPAR-gamma) lowers the levels of resistin and increases adiponectin, resulting in an improvement of glucose homeostasis. However, the first step to avoid insulin resistance should be an attempt to reduce body weight and to increase physical activity. These are successful means to avoid the development of type 2 diabetes from prediabetic states, as shown recently in 3 independent intervention trials.
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PMID:[From obesity to diabetes]. 1223 30


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