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)

Leukocyte type 12-lipoxygenase (12-LO) catalyzes the conversion of arachidonic acid (AA; C20:4) to 12-hydroperoxyeicosatetraenoic acid (12-HPETE) and linoleic acid (LA; C18:2) to 13-hydroperoxyoctadecadienoic acid (13-HPODE). Previous studies have demonstrated that 12-LO, but not 5- or 15-lipoxygenase (5-LO, 15-LO respectively), is specifically expressed in pancreatic -cells and is involved in regulating glucose-stimulated insulin secretion. Lipoxygenase products also have been linked with inflammatory pathways in endothelial cells, kidney mesangial cells, inflammatory bowel disease, and corneal epithelial cells. Therefore, 12-LO may play a role in cytokine mediated inflammation in pancreatic beta-cells (i.e. beta -cell dysfunction and cytotoxicity). Cytokines such as IL-1 stimulate both de novo 12-LO protein synthesis and enzyme activity in pancreatic beta-cells. The products generated by 12-LO may ultimately be involved in cellular events that lead to lipid peroxidation. Hydroperoxide and free radical production in beta-cells can activate intracellular signaling pathways that lead to cell death or may directly damage mitochondrial and plasma membranes. Increased 12-LO expression has also been found in islets from prediabetic Zucker fatty rats, a model that demonstrates insulin secretory defects similar to human type 2 diabetes. In this review, we present an overview of the 12-LO pathway in regulating glucose-stimulated insulin secretion in beta-cells as well as more recent data which supports the hypothesis that the 12-LO pathway participates in cytokine mediated beta-cell dysfunction and cytotoxicity.
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PMID:The role of 12-lipoxygenase in pancreatic -cells (Review). 985 29

TNF-alpha (so-called cachectin), IL-1 and 6 are important regulating agents in the homeostasis of energy in the organism, as among others they control processes of apoptosis and thus also the volume of adipose and muscular tissues. They are produced not only in immunocompetent cells but also in adipocytes and muscle cells. The cytokine system is then activated not only in tumours and infections but elevated values were found also in obesity, NIDDM, in myocardial infarction and in advanced decompensated cardiac patients. By acting on phosphorylation of IRS-1 and PI-3 kinase TNF-alpha promotes significantly insulin resistance, causes deterioration of diabetes, as well as elevated body temperature, sleepiness and anorexia. In a group of 65 patients, mostly with android obesity, in hyperleptinaemic and insulin resistant probands with coronarographically confirmed microvascular angina pectoris (n = 22) or IHD, mostly after a myocardial infarction (n = 43) with one or more significant stenoses on the epicardial coronary arteries in half the patients positive or elevated TNF-alpha was found and in 28% also IL-6. This increase did not correlate however with BMI, the percentage of body fat, IRI and C peptide levels nor with cortisol and leptin levels. Insulin resistant subjects had more frequently elevated homocysteine and Lp(a) values which are further two independent risk factors of atherothrombogenesis. Hyperhomocysteinaemia can be favourably influenced by vitamin fortification of the diet or by administration of folate and pyridoxine (1 tablet per day) involving negligible financial costs.
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PMID:[Relation between cytokines (TNF-alpha, IL-1 and 6) and homocysteine in android obesity and the phenomenon of insulin resistance syndromes]. 1042 20

In type 2 diabetes, chronic hyperglycemia is suggested to be detrimental to pancreatic beta cells, causing impaired insulin secretion. IL-1beta is a proinflammatory cytokine acting during the autoimmune process of type 1 diabetes. IL-1beta inhibits beta cell function and promotes Fas-triggered apoptosis in part by activating the transcription factor NF-kappaB. Recently, we have shown that increased glucose concentrations also induce Fas expression and beta cell apoptosis in human islets. The aim of the present study was to test the hypothesis that IL-1beta may mediate the deleterious effects of high glucose on human beta cells. In vitro exposure of islets from nondiabetic organ donors to high glucose levels resulted in increased production and release of IL-1beta, followed by NF-kappaB activation, Fas upregulation, DNA fragmentation, and impaired beta cell function. The IL-1 receptor antagonist protected cultured human islets from these deleterious effects. beta cells themselves were identified as the islet cellular source of glucose-induced IL-1beta. In vivo, IL-1beta-producing beta cells were observed in pancreatic sections of type 2 diabetic patients but not in nondiabetic control subjects. Similarly, IL-1beta was induced in beta cells of the gerbil Psammomys obesus during development of diabetes. Treatment of the animals with phlorizin normalized plasma glucose and prevented beta cell expression of IL-1beta. These findings implicate an inflammatory process in the pathogenesis of glucotoxicity in type 2 diabetes and identify the IL-1beta/NF-kappaB pathway as a target to preserve beta cell mass and function in this condition.
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PMID:Glucose-induced beta cell production of IL-1beta contributes to glucotoxicity in human pancreatic islets. 2836 91

Failure of insulin producing pancreatic beta-cells is a common characteristic of type 1 (insulin-dependent) and type 2 (insulin non-dependent) diabetes mellitus. Accumulating evidence suggests that programmed cell death (apoptosis) is the main form of beta-cell death in these disorders. The beta-cell is particularly sensitive to apoptotic stimuli due to the inherent features of the specialized beta-cell phenotype. In type 1 diabetes anti-beta-cell autoimmune reactivity delivers the apoptotic signals in the form of inflammatory mediators or T-cell effectors. In type 2 diabetes, the metabolic derangement is associated with production of inflammatory mediators in insulin-sensitive tissues leading elevated levels of circulating inflammatory mediators such as IL-6 and TNF. Further glucose has been suggested to induce beta-cell apoptosis via the induction of beta-cell synthesis of IL-1 which via autocrine action may elicit signalling cascades analogous to those seen in beta-cell destruction in type 1 diabetes. Considering the apparent importance of IL-1-beta signalling in beta-cell failure in both type 1 and type 2 diabetes, we here review the modulatory effect exerted on IL-1signalling by cellular characteristics related to the specialized beta-cell phenotype. We conclude that beta-cell differentiation signals (Pdx-1), glucose metabolism, calcium handling as well as regulation of naturally occurring inhibitors of cytokine signalling contribute to sensitize the beta-cell to apoptotic stimuli. We hypothesize that immunological stimuli in type 1 diabetes and metabolic/inflammatory signals in type 2 diabetes converge on common signalling pathways leading to beta-cell failure and destruction in these two diseases.
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PMID:Apoptotic signal transduction pathways in diabetes. 1455 18

Type 2 diabetes mellitus manifests itself in individuals who lose the ability to produce sufficient amounts of insulin to maintain normoglycaemia in the face of insulin resistance. The ability to secrete adequate amounts of insulin depends on beta-cell function and mass. Chronic hyperglycaemia is detrimental to pancreatic beta-cells, causing impaired insulin secretion and playing an essential role in the regulation of beta-cell turnover. This paper will address the effect of chronically elevated glucose levels on beta-cell turnover and function. In previous studies we have shown that elevated glucose concentrations induce apoptosis in human beta-cells due to an interaction between constitutively expressed Fas ligand and upregulated Fas. Human beta-cells produce interleukin (IL)-1beta in response to high glucose concentrations, independently of an immune-mediated process. This was antagonized by the IL-1 receptor antagonist (IL-1Ra), a naturally occurring anti-inflammatory cytokine also found in the beta-cell. Therefore the balance of IL-1beta and IL-1Ra may play a crucial role in the pathogenesis of diabetes. Inhibition of glucotoxicity represents a promising therapeutic stratagem in diabetes therapy to preserve functional beta-cell mass.
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PMID:Beta-cells in type 2 diabetes: a loss of function and mass. 1553 3

Regular exercise offers protection against all-cause mortality, primarily by protection against cardiovascular disease and Type 2 diabetes mellitus. The latter disorders have been associated with chronic low-grade systemic inflammation reflected by a two- to threefold elevated level of several cytokines. Adipose tissue contributes to the production of TNF-alpha, which is reflected by elevated levels of soluble TNF-alpha receptors, IL-6, IL-1 receptor antagonist, and C-reactive protein. We suggest that TNF-alpha rather than IL-6 is the driver behind insulin resistance and dyslipidemia and that IL-6 is a marker of the metabolic syndrome, rather than a cause. During exercise, IL-6 is produced by muscle fibers via a TNF-independent pathway. IL-6 stimulates the appearance in the circulation of other anti-inflammatory cytokines such as IL-1ra and IL-10 and inhibits the production of the proinflammatory cytokine TNF-alpha. In addition, IL-6 enhances lipid turnover, stimulating lipolysis as well as fat oxidation. We suggest that regular exercise induces suppression of TNF-alpha and thereby offers protection against TNF-alpha-induced insulin resistance. Recently, IL-6 was introduced as the first myokine, defined as a cytokine that is produced and released by contracting skeletal muscle fibers, exerting its effects in other organs of the body. Here we suggest that myokines may be involved in mediating the health-beneficial effects of exercise and that these in particular are involved in the protection against chronic diseases associated with low-grade inflammation such as diabetes and cardiovascular diseases.
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PMID:The anti-inflammatory effect of exercise. 1577 55

Chronic inflammation appears to play a critical role in type 2 diabetes and its complications. Here we tested the hypothesis that this inflammatory dysregulation affects the IL-1beta system and has functional consequences in the brain. Diabetic, db/db, and nondiabetic, db/+, mice were administered i.p. LPS, a potent cytokine inducer, at a dose of 100 microg/kg/mouse. db/db mouse innate immune-associated sickness behavior was 14.8, 33, 44.7, and 34% greater than that of db/+ mice at 2, 4, 8, and 12 h, respectively. When a fixed dose of LPS was used (5 microg/mouse), db/db mouse sickness was again enhanced 18.4, 22.2, and 14.5% at 4, 8, and 12 h as compared with db/+ mice. In diabetic mice, peritoneal macrophages produced more IL-1beta in response to LPS, and peritoneal levels of IL-1beta induced by LPS were increased. Importantly, IL-1R antagonist and type 2 IL-1 receptor (IL-1R2) failed to up-regulate in response to LPS in db/db mice. Finally, both peripheral and central administration of IL-1beta, itself, induced sickness in db/db mice that mimicked the effects of peripheral LPS and was significantly greater than that seen in db/+ mice. Taken together, these results indicate that IL-1beta-mediated innate immunity is augmented in db/db mice both at the periphery and in the brain, and the mechanism is due to diabetes-associated loss of IL-1beta counterregulation.
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PMID:IL-1beta-mediated innate immunity is amplified in the db/db mouse model of type 2 diabetes. 1581 29

Streptozotocin administration in newborn rats (nSTZ-rats) leads to adults with mild insulin deficiency and normoglycemia, and is accepted as a model of type 2 diabetes. We examined possible differences in the production of inflammatory mediators between healthy and nSTZ-rats after ischemia-reperfusion (I-R). Two-month-old control and nSTZ-rats were randomly separated into control and intestinal I-R groups. After reperfusion, samples were obtained from the portal vein (PV) infrahepatic cava vein (ICV), suprahepatic cava vein (SCV), jejunal wall, and pancreas. Nitric oxide (NO), lipid hydroperoxides (LPO), tumor necrosis factor alpha (TNF-alpha), 60 kDa receptor (sTNF-R1), 80 kDa (sTNF-R2), and intercellular adhesion molecule-1 (ICAM-1), were determined. After I-R, nSTZ-rats showed increased plasma concentrations of LPO, NO, ICAM-1 (0.5141 +/- 0.083 vs 0.024 +/- 0.003, ICV; 0.574 +/- 0.075 vs 0.023 +/- 0.003, SCV; 0.528 +/- 0.067 vs 0.027 +/- 0.003 PV; ng/ml), TNF-alpha (42.4 +/- 5.7 ICV, 248.4 +/- 28.2 SCV, and 33.6 +/- 4.0 PV. In n STZ-rats, vs 4.36 +/- 0.57, 4.74 +/- 0.77, and 3.16 +/- 0.32, respectively, in control rats; pg/ml), and sTNF-R1. Both TNF-alpha and NO plasma levels were higher in SCV than in ICV and PV after I-R. In addition, after I-R, jejunal wall of nSTZ-rats showed an increase of TNF-alpha IL-1, and IL-10 levels. A pre-existing state of glucose intolerance intensifies the inflammatory response after intestinal I-R.
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PMID:Glucose intolerance modifies the inflammatory response after intestinal ischemia-reperfusion. 1608 24

Hypertension, poor glycemic control and albuminuria are well known risk factors for diabetic nephropathy, but these factors do not explain all of the inter-individual variabilities in the rate of progression to kidney failure. Recent evidence showed that genetic predisposition affected the hyperglycemia-induced nephrotoxicity in patients with type 2 diabetes mellitus (DM). We reviewed the present state of knowledge concerning the relationship between genetics and diabetic nephropathy in type 2 DM. However, the results are inconclusive and the genetic determinants of diabetic nephropathy are not fully understood. In addition, genetic background of nephropathy in type 2 DM was thought to be more complex than in type 1 DM. Recent studies suggested that the inflammation would be an essential component of type 2 DM and its complications. We postulated that increased systemic and/or intrarenal inflammation in high glucose milieu is important in the pathogenesis of nephropathy in patients with type 2 DM. To investigate the impact of inflammation on diabetic nephropathy, we studied several polymorphisms in genes encoding inflammatory cytokine and chemokine in patients with type 2 DM. Among them, -511 C/T in interleukin-1beta (IL-1beta), tandem repeat in IL-1 receptor antagonist (IL-1Ra), -308 G/A in tumour necrosis factor-alpha (TNF-alpha) were significantly associated with an increased risk of kidney failure. In addition, some of them were remarkably different from those previously reported in the NCBI or literature based on the western population. Our results suggest that inflammation could play a pathogenic role in diabetic nephropathy in type 2 DM. A better understanding of genetic factors predisposing to diabetic nephropathy would not only help to identify diabetic patients at risk, but also be helpful to unveil the pathogenesis of DN.
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PMID:Genetics of diabetic nephropathy in type 2 DM: candidate gene analysis for the pathogenic role of inflammation. 1617 85

Different degrees of beta-cell failure and apoptosis are present in type 1 and type 2 diabetes. It has been recently suggested that high glucose-induced beta-cell apoptosis in type 2 diabetes shares a final common pathway with type 1 diabetes, involving interleukin-1beta (IL-1beta) production by beta-cells, nuclear factor-kappaB (NF-kappaB) activation, and death via Fas-FasL. The aim of this study was to test whether human islet exposure to high glucose in vitro, or to the type 2 diabetes environment in vivo, induces IL-1beta expression and consequent activation of NF-kappaB-dependent genes. Human islets were isolated from five normoglycemic organ donors. The islets were cultured for 48 h to 7 days at 5.6, 11, or 28 mmol/l glucose. For comparative purposes, islets were also exposed to IL-1beta. Gene mRNA expression levels were assessed by real-time RT-PCR in a blinded fashion. Culture of the human islets at 11 and 28 mmol/l glucose induced a four- to fivefold increase in medium insulin as compared with 5.6 mmol/l glucose, but neither IL-1beta nor IL-1 receptor antagonist (IL-1ra) expression changed. IL-1beta and IL-1ra protein release to the medium was also unchanged. Stimulated human monocytes, studied in parallel, released >50-fold more IL-1beta than the islets. There was also no glucose-induced islet Fas expression. Expression of the NF-kappaB-dependent genes IkappaB-alpha and monocyte chemoattractant protein (MCP)-1 was induced in human islets by IL-1beta but not by high glucose. In a second set of experiments, human islets were isolated from seven type 2 diabetic patients and eight control subjects. The findings on mRNA levels were essentially the same as in the in vitro experiments, namely the in vivo diabetic state did not induce IL-1beta, Fas, or MCP-1 expression in human islets, and also did not modify IL-1ra expression. The present findings suggest that high glucose in vitro, or the diabetic milieu in vivo, does not induce IL-1beta production or NF-kappaB activation in human islets. This makes it unlikely that locally produced IL-1beta is an important mediator of glucotoxicity to human islets and argues against the IL-1beta-NF-kappaB-Fas pathway as a common mediator for beta-cell death in type 1 and type 2 diabetes.
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PMID:Is there a role for locally produced interleukin-1 in the deleterious effects of high glucose or the type 2 diabetes milieu to human pancreatic islets? 1624 50


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