UMLS:C0028754 - FACTA Search

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Query: UMLS:C0028754 (obesity)
124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The perilipins are highly phosphorylated adipocyte proteins that are localized at the surface of the lipid droplet. With activation by protein kinase A, perilipins translocate away from the lipid droplet and allow hormone-sensitive lipase to hydrolyze the adipocyte triglycerides to release nonesterified fatty acids (NEFA). Because of the potential importance of adipocyte lipolysis to obesity and insulin resistance, we measured perilipin protein and mRNA levels in nondiabetic subjects with varying degrees of insulin resistance. By Northern and Western blotting, we could detect perilipin A, but not perilipin B. Perilipin A protein and mRNA levels were quantitated and were highly correlated with each other. There was a significant positive relationship between perilipin expression and obesity (r = 0.55; P < 0.01, perilipin mRNA vs. percent body fat). However, there was no significant relationship between perilipin expression and blood NEFA, nor was there a significant relationship between perilipin expression and insulin resistance, using the insulin sensitivity index derived from the iv glucose tolerance test with minimal modeling. In addition, there was no significant relationship between perilipin and adipocyte or systemic inflammatory markers, such as TNFalpha, IL-6, and adiponectin. Thus, perilipin was elevated in obese subjects, perhaps as a compensatory mechanism to limit basal lipolysis. However, there was no relationship between perilipin and insulin resistance.
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PMID:Perilipin expression in human adipose tissue is elevated with obesity. 1500 33

Liposuction is one of the more common elective surgical procedures in the US and is supposed to be on the increase. There are no reported studies specifically addressing the metabolic sequelae of liposuction in obesity. The aim of the present study was to investigate the role of large-volume liposuction on insulin resistance and circulating inflammatory markers in obese people. Thirty healthy premenopausal obese (body mass index (BMI) from 30 to 45) and 30 age-matched normal weight (BMI<25) women were studied. In obese women, insulin sensitivity, as measured by the Homeostasis Model Assessment (HOMA=fasting plasma glucose x fasting serum insulin divided by 25), as well as serum adiponectin, the novel adipocytokine with insulin sensitising properties, were significantly lower, as compared with nonobese women (p<0.01), indicating insulin resistance; on the contrary, serum concentrations of the proinflammatory cytokines IL-6, IL-18 and TNF-alpha, as well as the sensitive marker of inflammation C-reactive protein, were significantly higher (p<0.01). All obese women were submitted to a single large volume liposuction (superwet technique): the mean aspirate volume was 3540 ml (range 2550-4670), corresponding to a net lipid loss of 2.7+/-0.7 kg (mean+/-SD). After six months of stable body weight after liposuction, women were less insulin resistant (p<0.05), had reduced concentrations of IL-6, IL-18, TNF-alpha and CRP (p<0.05-0.02), and increased serum levels of adiponectin (p<0.02) and HDL-cholesterol (p<0.05). There was a significant correlation between the amount of fat aspirate and changes in HOMA (r=0.28, p<0.05), TNF-alpha (r=0.31, p<0.02), and adiponectin (r=-0.34, p<0.02), as well as between the decrease in TNF-alpha and the increase in adiponectin after the surgical procedure (r=-0.45, p<0.01). Our study demonstrates that liposuction is safe and free of metabolic sequelae in obese women, pending a careful screening of the patient. Moreover, it is associated with amelioration of insulin resistance and reduced circulating markers of vascular inflammation which may help obese subjects to reduce their cardiovascular risk.
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PMID:Effect of liposuction on insulin resistance and vascular inflammatory markers in obese women. 1592 45

It is now recognized that the white adipose tIssue (WAT) produces a variety of bioactive peptIdes, collectively termed "adipokines". Alteration of WAT mass in obesity or lipoatrophy, affects the production of most adipose secreted factors. Since both conditions are associated with multiple metabolic disorders and increased risk of cardiovascular diseases, the Idea has emerged that WAT could be instrumental in these complications, by virtue of its secreted factors. Several adipokines are increased in the obese state and have been implicated in hypertension (angiotensinogen), impaired fibrinolysis (PAI-1) and insulin resistance (ASP, TNFalpha, IL-6, resistin). Conversely, leptin and adiponectin both exert an insulin-sensitizing effect, at least in part, by favoring tIssue fatty-acId oxIdation through activation of AMP-activated kinase. In obesity, insulin resistance has been linked to leptin resistance and decreased plasma adiponectin. In lipoatrophic mice, where leptin and adiponectin circulating levels are low, administration of the two adipokines synergistically reverses insulin resistance. Leptin and adiponectin also have distinct properties: leptin, as a long-term integrative signal of energy store and adiponectin, as a potent anti-atherogenic agent. The thiazolIdinedione anti-diabetic drugs increase endogenous adiponectin production in rodents and humans, supporting the Idea that the development of new drugs targeting adipokines might represent a promising therapeutic approach to protect obese patients from insulin resistance and atherosclerosis.
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PMID:Adipose tissue and adipokines: for better or worse. 1502 93

Obesity is a risk factor for type 2 diabetes and cardiovascular diseases. The hypothesis that cytokines could play a role in the pathophysiology of obesity and insulin resistance is suggested in the last few years. We showed a positive correlation between circulating interleukin (IL-6) levels and obesity and insulin resistance suggesting that IL-6 could be involved in insulin resistance in humans. We showed a decrease of both circulating and adipose tissue IL-6 levels in non-diabetic obese subjects after a very low calorie diet program inducing weight loss. This suggests that adipose tissue could be involved in the regulation of circulating IL-6 levels in these subjects. Adipose tissue is also involved in lipodystrophies particularly in HIV patients on antiviral therapy. We showed an alteration of the SREBP-1 transcription step in subcutaneous abdominal adipose tissue from HIV patients. We found an inverse correlation between circulating adiponectin levels and both insulin resistance and cardiovascular risk factors such as CRP levels and apolipoprotein B/A1 ratio. These findings suggest that adipose tissue is involved in insulin resistance in humans particularly via adipocytokine secretion.
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PMID:[Insulin resistance and adipose tissue gene expression in humans]. 1504 87

The circulating level of the inflammatory cytokine interleukin (IL)-6 is elevated in various insulin-resistant states including type 2 diabetes, obesity, cancer, and HIV-associated lipodystrophy. To determine the role of IL-6 in the development of insulin resistance, we examined the effects of IL-6 treatment on whole-body insulin action and glucose metabolism in vivo during hyperinsulinemic-euglycemic clamps in awake mice. Pretreatment of IL-6 blunted insulin's ability to suppress hepatic glucose production and insulin-stimulated insulin receptor substrate (IRS)-2-associated phosphatidylinositol (PI) 3-kinase activity in liver. Acute IL-6 treatment also reduced insulin-stimulated glucose uptake in skeletal muscle, and this was associated with defects in insulin-stimulated IRS-1-associated PI 3-kinase activity and increases in fatty acyl-CoA levels in skeletal muscle. In contrast, we found that co-treatment of IL-10, a predominantly anti-inflammatory cytokine, prevented IL-6-induced defects in hepatic insulin action and signaling activity. Additionally, IL-10 co-treatment protected skeletal muscle from IL-6 and lipid-induced defects in insulin action and signaling activity, and these effects were associated with decreases in intramuscular fatty acyl-CoA levels. This is the first study to demonstrate that inflammatory cytokines IL-6 and IL-10 alter hepatic and skeletal muscle insulin action in vivo, and the mechanism may involve cytokine-induced alteration in intracellular fat contents. These findings implicate an important role of inflammatory cytokines in the pathogenesis of insulin resistance.
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PMID:Differential effects of interleukin-6 and -10 on skeletal muscle and liver insulin action in vivo. 1504 22

During the last 10 years, various adipocytokines have been described which influence insulin sensitivity profoundly and might, therefore, potentially link obesity and insulin resistance. Recently, monocyte chemoattractant protein (MCP)-1 was characterized as a novel adipose-secreted factor upregulated in obesity and insulin resistance that impairs insulin signaling in fat cells in vitro and can be found in atherosclerotic lesions. To clarify expression and regulation of this adipocytokine, MCP-1 mRNA was measured by quantitative real-time reverse transcription-polymerase chain reaction during differentiation of 3T3-L1 adipocytes and after treatment with various hormones known to induce insulin resistance. Interestingly, MCP-1 synthesis was significantly downregulated between 43% and 68% during differentiation of 3T3-L1 preadipocytes. Furthermore, 10 ng/ml tumor necrosis factor alpha, 100 nM insulin, 500 ng/ml growth hormone (GH), and 30 ng/ml interleukin (IL)-6-induced MCP-1 mRNA by up to 124-, 23-, 8-, and 2.5-fold, respectively, in a time-dependent fashion with significant stimulation seen at concentrations as low as 0.5 ng/ml GH and 30 ng/ml IL-6. In contrast, the glucocorticoid dexamethasone potently downregulated MCP-1 with significant suppression detectable at concentrations as low as 3 nM and as early as 2h after effector addition. Studies using pharmacological inhibitors suggested that the positive effects of GH and IL-6 on MCP-1 synthesis are at least in part mediated by janus kinase 2 and p44/42 mitogen-activated protein kinase. Taken together, our results show a differential regulation of MCP-1 mRNA by insulin resistance-inducing hormones and support the view that this adipocytokine might be an interesting novel candidate linking insulin resistance, obesity, and atherosclerosis. This adipocytokine could thus be a potential pharmacological target for the treatment of impaired insulin sensitivity.
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PMID:Monocyte chemoattractant protein 1 expression is stimulated by growth hormone and interleukin-6 in 3T3-L1 adipocytes. 1506 99

Hyperinsulinemic hyperandrogenism with anovulation, the so-called polycystic ovary syndrome (PCOS), is the most frequent endocrine disorder of young women. One of the stigmata of PCOS is a deficit of lean mass and an excess of fat, in particular, abdominal fat, even in the absence of obesity. Adiponectin and IL-6 are among the adipocytokines that have recently been related to abdominal fat excess, insulin resistance states, and cardiovascular disease risk. We studied the effects of two new treatment options, ethinylestradiol-drospirenone and flutamide-metformin, and of their combination on adipocytokinemia and body adiposity in adolescents and women with PCOS. Adolescents with PCOS (n = 32; age, approximately 15 yr; body mass index, approximately 22 kg/m(2)) were randomly assigned to receive the oral contraceptive (OC) ethinylestradiol-drospirenone, or the low-dose generic duo of flutamide (62.5 mg/d) plus metformin (850 mg/d). Young women with PCOS (n = 22; age, approximately 19 yr; body mass index, approximately 22 kg/m(2)) were randomized to receive the same OC, either alone or with flutamide-metformin. Fasting blood glucose, serum insulin, lipids, androgens, IL-6, adiponectin, and body composition (by absorptiometry) were assessed at the start, and after 3 and/or 9 months. At the start, serum concentrations of the proinflammatory IL-6 were high, and those of the antiinflammatory adiponectin were low; body composition was adipose in each subpopulation. Abnormal adipocytokine levels, hypertriglyceridemia, and body adiposity diverged further from the norm in adolescents on OC; in contrast, girls on flutamide-metformin reverted all study indices toward normal, lost part of their fat excess, and reduced their lean mass deficit. In comparison to the girls on OC, those on flutamide-metformin lost a mean of approximately 4 kg of fat and gained approximately 4 kg of lean mass. Similarly, abnormal adipocytokine levels and adiposity were aggravated in women on OC alone and improved in women on OC plus flutamide-metformin; within 9 months, the latter subgroup lost a mean of approximately 3 kg of fat and gained approximately 3 kg of lean mass, in comparison to women on OC alone. In conclusion, young and nonobese PCOS patients were found to be in a low-grade, chronic inflammation state, and to have a body adiposity that evolves according to the balance of circulating adipocytokines and lipids, rather than to androgen excess or fasting hyperinsulinemia. Monotherapy with ethinylestradiol-drospirenone may not be a prime choice for PCOS, given its inefficacy to attenuate abnormal adipocytokine levels and body adiposity; ethinylestradiol-drospirenone plus flutamide-metformin, however, is a first OC combination that was found capable of reverting both the adipocytokine balance and the body composition toward normal, and that may therefore improve the long-term cardiovascular perspectives of women with PCOS.
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PMID:Ethinylestradiol-drospirenone, flutamide-metformin, or both for adolescents and women with hyperinsulinemic hyperandrogenism: opposite effects on adipocytokines and body adiposity. 1507 Sep 17

Increased levels of IL-6 add further risk to the impact of obesity in respect to the development of type 2 diabetes mellitus (T2DM). A C-174G polymorphism within the IL-6 promoter region was shown to influence transcription rate of IL-6. We made use of a nested case-control study within the European Prospective Investigation into Cancer and Nutrition-Potsdam cohort of 27,548 individuals, selecting 188 T2DM cases and 376 controls to investigate this polymorphism in respect to development of T2DM. This polymorphism was found to modify the correlation between body mass index (BMI) and IL-6 by showing a much stronger increase of IL-6 at increased BMI for CC genotypes compared with GG genotypes. Interestingly, C-174G polymorphism was found to be an effect modifier for the impact of BMI regarding T2DM. Whereas BMI greater than or equal to 28 kg/m(2) increased the risk of T2DM 3.44-fold [95% confidence interval (CI), 1.34- to 8.24-fold] for GG genotypes and 2.94-fold (95% CI, 1.56- to 5.56-fold) for GC genotypes, we found a 17.68-fold (95% CI, 3.57- to 87.66-fold) increase in risk for CC genotypes. In conclusion, obese individuals with BMI greater than or equal to 28 kg/m(2) carrying the CC genotype showed a more than 5-fold increased risk of developing T2DM compared with the remaining genotypes and, hence, might profit most from weight reduction.
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PMID:Body mass index and C-174G interleukin-6 promoter polymorphism interact in predicting type 2 diabetes. 1507 Sep 60

Insulin resistance is an important component of the metabolic syndrome associated with obesity. Early-stage insulin-resistance and related mild glucose intolerance may be compensated by increased insulin secretion. When combined with impaired insulin secretion, insulin resistance plays an important role in type 2 diabetes (1). Insulin-resistance is also associated with a variety of pathological conditions, including trauma, infection, and cancer. Obesity and type 2 diabetes are the most common metabolic diseases in Western societies, together affecting as much as half of the adult population (2). The prevalence of these conditions is not only high, but continues to increase. We have only recently come to appreciate the role of fat, especially visceral fat, as an endocrine organ. Visceral fat is the source of a number of substances which might play a role in the development of insulin resistance. Among the latter are tumor necrosis factor-alpha (TNF-alpha), adiponectin, IL-6, resistin and free fatty acids. This review will discuss the regulation of insulin responses by TNF-alpha and evidence supporting the hypothesis that over expression of TNF-alpha plays a role in the pathophysiology of insulin resistance.
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PMID:The role of TNF-alpha in insulin resistance. 1514 98

Obesity is an epidemic disease that threatens to inundate health care resources by increasing the incidence of diabetes, heart disease, hypertension, and cancer. These effects of obesity result from two factors: the increased mass of adipose tissue and the increased secretion of pathogenetic products from enlarged fat cells. This concept of the pathogenesis of obesity as a disease allows an easy division of disadvantages of obesity into those produced by the mass of fat and those produced by the metabolic effects of fat cells. In the former category are the social disabilities resulting from the stigma associated with obesity, sleep apnea that results in part from increased parapharyngeal fat deposits, and osteoarthritis resulting from the wear and tear on joints from carrying an increased mass of fat. The second category includes the metabolic factors associated with distant effects of products released from enlarged fat cells. The insulin-resistant state that is so common in obesity probably reflects the effects of increased release of fatty acids from fat cells that are then stored in the liver or muscle. When the secretory capacity of the pancreas is overwhelmed by battling insulin resistance, diabetes develops. The strong association of increased fat, especially visceral fat, with diabetes makes this consequence particularly ominous for health care costs. The release of cytokines, particularly IL-6, from the fat cell may stimulate the proinflammatory state that characterizes obesity. The increased secretion of prothrombin activator inhibitor-1 from fat cells may play a role in the procoagulant state of obesity and, along with changes in endothelial function, may be responsible for the increased risk of cardiovascular disease and hypertension. For cancer, the production of estrogens by the enlarged stromal mass plays a role in the risk for breast cancer. Increased cytokine release may play a role in other forms of proliferative growth. The combined effect of these pathogenetic consequences of increased fat stores is an increased risk of shortened life expectancy.
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PMID:Medical consequences of obesity. 1518 Oct 27

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