Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fat tissue produces a variety of secreted proteins (adipocytokines) with important roles in metabolism. We isolated a newly identified adipocytokine, visfatin, that is highly enriched in the visceral fat of both humans and mice and whose expression level in plasma increases during the development of obesity. Visfatin corresponds to a protein identified previously as pre-B cell colony-enhancing factor (PBEF), a 52-kilodalton cytokine expressed in lymphocytes. Visfatin exerted insulin-mimetic effects in cultured cells and lowered plasma glucose levels in mice. Mice heterozygous for a targeted mutation in the visfatin gene had modestly higher levels of plasma glucose relative to wild-type littermates. Surprisingly, visfatin binds to and activates the insulin receptor. Further study of visfatin's physiological role may lead to new insights into glucose homeostasis and/or new therapies for metabolic disorders such as diabetes.
 ...
PMID:Visfatin: a protein secreted by visceral fat that mimics the effects of insulin. 1796 37

White adipose tissue is no longer considered an inert tissue mainly devoted to energy storage but is emerging as an active participant in regulating physiologic and pathologic processes, including immunity and inflammation. Macrophages are components of adipose tissue and actively participate in its activities. Furthermore, cross-talk between lymphocytes and adipocytes can lead to immune regulation. Adipose tissue produces and releases a variety of proinflammatory and anti-inflammatory factors, including the adipokines leptin, adiponectin, resistin, and visfatin, as well as cytokines and chemokines, such as TNF-alpha, IL-6, monocyte chemoattractant protein 1, and others. Proinflammatory molecules produced by adipose tissue have been implicated as active participants in the development of insulin resistance and the increased risk of cardiovascular disease associated with obesity. In contrast, reduced leptin levels might predispose to increased susceptibility to infection caused by reduced T-cell responses in malnourished individuals. Altered adipokine levels have been observed in a variety of inflammatory conditions, although their pathogenic role has not been completely clarified.
 ...
PMID:Adipose tissue, adipokines, and inflammation. 1586 43

Recently, visfatin was characterized as a novel adipo-cytokine that is upregulated in obesity and exerts insulin-mimetic effects in various tissues. To clarify expression and regulation of this adipocytokine, visfatin mRNA was measured by quantitative real-time reverse transcription-polymerase chain reaction in 3T3-L1 adipocytes during adipogenesis and after treatment with various hormones known to alter insulin sensitivity. Visfatin expression was about 6-fold higher in 3T3-L1 adipocytes in vitro as compared with epididymal fat in vivo and increased during adipogenic conversion more than 3-fold. Interestingly, 100 nM dexamethasone significantly increased visfatin mRNA by almost 1.5-fold. In contrast, 500 ng/ml growth hormone (GH), 10 ng/ml tumor necrosis factor (TNF) alpha, and 10 microM isoproterenol downregulated visfatin expression by 45%, 36%, and 43% respectively. Insulin did not influence synthesis of this adipocytokine. The effects of dexamethasone, GH, TNFalpha and isoproterenol were time- and dose-dependent. Furthermore, activation of G(s)-protein-coupled pathways by forskolin and cholera toxin was sufficient to significantly downregulate visfatin mRNA. Taken together, our results show a differential regulation of visfatin mRNA by insulin resistance-inducing hormones, supporting the view that this adipo-cytokine might be an interesting novel candidate linking core components of the metabolic syndrome such as obesity and insulin resistance.
 ...
PMID:Hormonal regulation of the novel adipocytokine visfatin in 3T3-L1 adipocytes. 1593 Jan 60

Various adipocyte-secreted factors have been described which profoundly affect insulin sensitivity and might potentially link obesity, insulin resistance and cardiovascular disease. Among those, adiponectin, visfatin and omentin appear as insulin-sensitising adipocytokines, whereas TNF-alpha, IL-6 and resistin induce insulin resistance. Moreover, leptin is a fat-derived key regulator of appetite and energy expenditure. Due to their profound effect on whole-body glucose and energy metabolism, adipocytokines have attracted interest as potential new therapeutics for diabetes mellitus and obesity. The current knowledge on function, regulation and therapeutic potential of various adipocytokines, as well as their clinical implications, are discussed in this review.
 ...
PMID:Therapeutic perspectives of adipocytokines. 1595 17

Recently, adipocytes have been shown to be endocrine cells that secrete a variety of bioactive substances-the so-called adipocytokines. Among adipocytokines, tumor necrotizing factor alpha, plasminogen activator inhibitor 1, and heparin-binding epidermal growth factor-like growth factor are produced in adipocytes as well as already known organs, and they contribute to the development of vascular diseases. Visfatin is a very recently discovered visceral fat-specific protein that may be related to the development of obesity-related diseases such as diabetes mellitus and cardiovascular disease. In contrast to these adipocytokines, adiponectin, also a newfound adipose tissue-specific collagen-like protein, has been noted recently as an important antiatherogenic as well as antidiabetic protein. The function of adipocytokine secretion might be regulated dynamically by nutritional state. Visceral fat accumulation causes dysfunction of adipocytes including oversecretion of tumor necrotizing factor alpha, plasminogen activator inhibitor 1, and heparin-binding epidermal growth factor-like growth factor, as well as hyposecretion of adiponectin, which results in the development of a variety of metabolic and circulatory diseases. In this review, the importance of adipocytokines, including adiponectin, is discussed with respect to atherosclerosis.
 ...
PMID:Adipocytokines and metabolic syndrome. 1596 78

Human obesity-related diabetes and the accompanying metabolic disorders have been specifically linked to increased visceral adipose tissue mass. Understanding the differences in biology of the two human fat depots (visceral and subcutaneous) might hold the key to therapeutic strategies aimed at reducing obesity-induced insulin resistance and alleviating symptoms of the metabolic syndrome. Visfatin (pre-B-cell colony-enhancing factor, PBEF) is a novel adipokine that appears to be preferentially produced by visceral adipose tissue and has insulin-mimetic actions. Could this molecule hold the key to future treatments for type 1 and 2 diabetes? This article discusses the pros and cons of visfatin action and how it might affect future therapeutic strategies.
 ...
PMID:Visfatin: the missing link between intra-abdominal obesity and diabetes? 1600 82

Adipose tissue, in addition to the storage of lipids function for lipids, plays active roles in normal metabolic homeostasis and in the development of several diseases, such as type 2 diabetes, dyslipaemia and atherosclerosis. These roles are mediated by adipocytokines, factors secreted by adipose tissue. These include tumor necrosis factors (TNF)-alpha, leptin, resistin, adiponectin or visfatin. Adipocytokines act in an autocrine, paracrine and endocrine manner. Adiponectin is a peculiar adipocytokine because in contrast to the markedly increased levels of leptin, resistin or TNF-alpha in obesity, its level is negatively correlated with body mass index, and is decreased in presence of insulin resistance and in type 2 diabetes. Adiponectin may play a crucial role in the development of diabetes mellitus and high adiponectin levels should protect against impairment of glucose metabolism. Moreover, adipocytokines are involved in the pathogenesis of vascular diseases and may represent a link between obesity, diabetes, inflammation and atherosclerosis. Weight loss, exercise and some antidiabetic drugs also influence plasma adipocytokines levels. For instance, thiazolidinediones treatment in patients with type 2 diabetes resulted in an increased in plasma adiponectin levels and a decrease in circulating TNF-alpha concentrations.
 ...
PMID:[Adipocytokines: link between obesity, type 2 diabetes and atherosclerosis]. 1603 96

A variety of adipocytokines and peptides secreted from adipocytes have been considered to play a crucial role in obesity, insulin resistance, and type 2 diabetes. Recently, visfatin, a new adipocytokine, known as a pre-B cell colony-enhancing factor, has been isolated from visceral fat deposits. It has been shown to activate insulin receptors in a manner different from insulin. To understand the role of adipocytokines in improving insulin sensitivity via activation of the nuclear receptor peroxisome proliferator-activated receptor-alpha (PPAR-alpha) and -gamma (PPAR-gamma), we examined the expression of visfatin, adiponectin, and TNF-alpha in visceral fat depots of Otsuka Long-Evans Tokushima fatty (OLETF) rats from early to advanced diabetic stage (from 28 to 40 weeks of age). Serum glucose and insulin concentrations significantly (P<0.05) decreased in rosiglitazone or fenofibrate-treated OLETF rats compared to untreated OLETF rats. Rosiglitazone significantly increased serum adiponectin concentration from 20 to 40 weeks of age (P<0.05), whereas fenofibrate reduced TNF-alpha concentration. The expression of visfatin and adiponectin mRNA in visceral fat deposits was elevated by rosiglitazone or fenofibrate treatments when compared to untreated OLETF rats (P<0.05), whereas, TNF-alpha mRNA was down-regulated by these drugs (P<0.05). These results suggest that rosiglitazone and fenofibrate may prevent type 2 diabetes by regulating adipocytokines including visfatin, adiponectin, and TNF-alpha.
 ...
PMID:Effect of PPAR-alpha and -gamma agonist on the expression of visfatin, adiponectin, and TNF-alpha in visceral fat of OLETF rats. 1615 99

Various peripheral tissues show circadian rhythmicity, which is generated at the cellular level by their own core oscillators that are composed of transcriptional/translational feedback loops involving a set of clock genes. Although the circulating levels of some adipocytokines, i.e. bioactive substances secreted by adipocytes, are on a 24-h rhythmic cycle, it remains to be elucidated whether the clock gene system works in adipose tissue. To address this issue, we investigated the daily mRNA expression profiles of the clock genes and adipocytokines in mouse perigonadal adipose tissues. In C57BL/6J mice, all transcript levels of the clock genes (Bmal1, Per1, Per2, Cry1, Cry2, and Dbp) and adipocytokines (adiponectin, resistin, and visfatin) clearly showed 24-h rhythms. On the other hand, the rhythmic expression of these genes was mildly attenuated in obese KK mice and greatly attenuated in more obese, diabetic KK-A(y) mice. Obese diabetes also diminished the rhythmic expression of the clock genes in the liver. Interestingly, a 2-wk treatment of KK and KK-A(y) mice with pioglitazone impaired the 24-h rhythmicity of the mRNA expression of the clock genes and adipocytokines despite the antidiabetic effect of the drug. In contrast, pioglitazone improved the attenuated rhythmicity in the liver. These findings suggest that the intracellular clock gene system acts in visceral adipose tissues as well as liver and is influenced by the conditions of obesity/type 2 diabetes and pioglitazone treatment.
 ...
PMID:Rhythmic messenger ribonucleic acid expression of clock genes and adipocytokines in mouse visceral adipose tissue. 1616 17

Visceral and subcutaneous adipose tissue display important metabolic differences that underlie the association of visceral obesity with obesity-related cardiovascular and metabolic alterations. Recently, visfatin was identified as an adipokine, which is predominantly secreted from visceral adipose tissue both in humans and mice. In this study, we examined whether visfatin plasma concentrations (using enzyme immunosorbent assay) and mRNA expression (using RT-PCR) in visceral and subcutaneous fat correlates with anthropometric and metabolic parameters in 189 subjects with a wide range of obesity, body fat distribution, insulin sensitivity, and glucose tolerance. Visfatin plasma concentration correlates positively with the visceral visfatin mRNA expression (r(2) = 0.17, P < 0.0001), BMI (r(2) = 0.062, P = 0.004), percent body fat (r(2) = 0.048, P = 0.01), and negatively with subcutaneous visfatin mRNA expression (r(2) = 0.18, P < 0.0001). However, in a subgroup of 73 individuals, in which visceral fat mass was calculated from computed tomography scans, there was no correlation between plasma visfatin concentrations and visceral fat mass. We found no significant correlation between visfatin plasma concentrations and parameters of insulin sensitivity, including fasting insulin, fasting plasma glucose concentrations, and the glucose infusion rate during the steady state of an euglycemic-hyperinsulinemic clamp independent of percent body fat. Visfatin gene expression was not different between visceral and subcutaneous adipose tissue in the entire study group nor in selected subgroups. We found a significant correlation between visceral visfatin gene expression and BMI (r(2) = 0.06, P = 0.001) and percent body fat (measured using dual-energy X-ray absorptiometry) (r(2) = 0.044, P = 0.004), whereas no significant association between BMI or percent body fat and subcutaneous visfatin mRNA expression existed (both P >0.5). In conclusion, visfatin plasma concentrations and visceral visfatin mRNA expression correlated with measures of obesity but not with visceral fat mass or waist-to-hip ratio. In addition, we did not find differences in visfatin mRNA expression between visceral and subcutaneous adipose tissue in humans.
 ...
PMID:Plasma visfatin concentrations and fat depot-specific mRNA expression in humans. 1618 92


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