Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Advanced glycation end products (AGEs) include a variety of protein adducts whose accumulation alters the structure and function of tissue proteins and stimulates cellular responses. They have been implicated in tissue damage associated with diabetic complications. To assess the possible link between AGE accumulation and the development of diabetic nephropathy (DN), we have examined the immunohistochemical localization of various AGE structures postulated to date, i.e., pentosidine, Nepsilon-(carboxymethyl)lysine (CML), and pyrraline, in diabetic and control kidneys. CML and pentosidine accumulate in the expanded mesangial matrix and thickened glomerular capillary walls of early DN and in nodular lesions and arterial walls of advanced DN, but were absent in control kidneys. By contrast, pyrraline was not found within diabetic glomeruli but was detected in the interstitial connective tissue of both normal and diabetic kidneys. Although the distribution of pyrraline was topographically identical to type III collagen, distribution of pentosidine and CML was not specific for collagen type, suggesting that difference in matrix protein composition per se could not explain heterogeneous AGE localization. Since oxidation is linked closely to the formation of pentosidine and CML, we also immunostained malondialdehyde (MDA), a lipid peroxidation product whose formation is accelerated by oxidative stress, assuming that local oxidative stress may serve as a mechanism of pentosidine and CML accumulation. Consistent with our assumption, diabetic nodular lesions were stained positive for MDA. These findings show that AGE localization in DN varies according to AGE structure, and suggest that the colocalization of markers of glycoxidation (pentosidine and CML) with a marker of lipid peroxidation reflects a local oxidative stress in association with the pathogenesis of diabetic glomerular lesions. Thus, glycoxidation markers may serve as useful biomarkers of oxidative damage in DN.
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PMID:Immunohistochemical colocalization of glycoxidation products and lipid peroxidation products in diabetic renal glomerular lesions. Implication for glycoxidative stress in the pathogenesis of diabetic nephropathy. 939 45

Increases in extracellular matrix (ECM) and changes in its components have been documented in the glomeruli of diabetic nephropathy. Advanced glycation end products formed by glycoxidation have been shown to induce the synthesis of ECM components and transforming growth factor beta (TGF-beta), suggesting that advanced glycation end products may be involved in the etiology of imbalance of ECM components in diabetic glomerulosclerosis. The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an inbred strain that spontaneously develops non-insulin-dependent diabetes mellitus which progresses to diabetic glomerulosclerosis. Nepsilon-(carboxymethyl)lysine (CML) is known to be formed by glycoxidation. To clarify the involvement of glycoxidation in diabetic nephropathy, we examined the localization of CML, ECM components, and TGF-beta1 in the glomeruli of OLETF rats. The amounts of alpha3(IV) collagen, type VI collagen, and fibronectin were significantly increased in the glomeruli of OLETF rats, whereas the heparan sulfate proteoglycan levels were decreased. After 6 months of age, CML levels were significantly increased in the mesangial area of the glomeruli in these animals. The overexpression of TGF-beta1 preceded the increase in glomerular ECM components. The present study demonstrated that the accumulation of CML precedes the changes of glomerular ECM components in the glomeruli during the course of diabetic nephropathy, suggesting that glycoxidation may be one of the major causes of diabetic glomerulosclerosis.
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PMID:Accumulation of Nsigma-(carboxy-methyl)lysine and changes in glomerular extracellular matrix components in Otsuka Long-Evans Tokushima fatty rat: a model of spontaneous NIDDM. 968 63

Aminoguanidine, an inhibitor of advanced glycation reactions in vitro, inhibits the development of diabetic complications in animal models of diabetes, suggesting that it acts by inhibition of advanced glycation reactions in vivo. However, effects of aminoguanidine on the formation of specific advanced glycation end-products (AGEs) in vivo have not been rigorously examined. Therefore, we studied the effects of aminoguanidine on the formation of pentosidine and N(epsilon)-(carboxymethyl)lysine (CML), measured by analytical chemical methods, in collagen of streptozotocin-diabetic Lewis rats at doses which ameliorated urinary albumin excretion, an index of diabetic nephropathy. At 12 weeks, diabetic animals had fivefold higher blood glucose, threefold higher glycated hemoglobin and fivefold higher collagen glycation, compared to metabolically healthy controls; pentosidine and CML in skin collagen were increased by approximately 30 and 150%, respectively. Administration of aminoguanidine, 50 mg/kg by daily intraperitoneal injection, significantly inhibited the development of albuminuria (approximately 60%, P < 0.01) in diabetic rats, without an effect on blood glucose or glycation of hemoglobin or collagen. Surprisingly, aminoguanidine failed to inhibit the increase in pentosidine and CML in diabetic rat skin collagen. Similar results were obtained in an independent experiment in which aminoguanidine was administered in drinking water at a dose of 0.5 g/l. We conclude that the therapeutic benefits of aminoguanidine on albuminuria may not be the result of inhibition of AGE formation.
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PMID:Aminoguanidine inhibits albuminuria, but not the formation of advanced glycation end-products in skin collagen of diabetic rats. 1022 60

Prolonged incubation of proteins with reducing sugar produces advanced glycation end products (AGEs), which are implicated as factors for aging and diabetic complications. We previously demonstrated the presence of N(epsilon)-(carboxymethyl)lysine (CML), one of the main AGE structures, in human and animal tissues using a monoclonal anti-CML antibody (6D12). These findings suggest that CML structures present in vivo could serve as immunogens to generate autoantibodies. This suggestion was tested in the present study. First, plasma samples from diabetic rats reacted positively with AGE bovine serum albumin (BSA). These reactivities increased with the duration of diabetic states and were inhibited specifically by CML-BSA. Second, a fraction purified from plasma of diabetic patients, which bound to AGE-BSA, showed a positive reaction to CML-BSA and furthermore also to human lens proteins, which are known to undergo CML modification in vivo. Finally, patients with renal failure caused by diabetes or nondiabetic pathologies had a higher autoantibody activity against CML structure than that in normal subjects or diabetic patients without renal failure. These results indicate that CML accumulated in vivo serves as an immunological epitope to generate an autoantibody specific for CML that might be used as a potential marker for diabetic nephropathy or chronic renal failure.
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PMID:Autoantibody against N(epsilon)-(carboxymethyl)lysine: an advanced glycation end product of the Maillard reaction. 1048 Jun 17

Advanced glycation end products (AGE) contribute to diabetic tissue injury by two major mechanisms, i.e., the alteration of extracellular matrix architecture through nonenzymatic glycation, with formation of protein crosslinks, and the modulation of cellular functions through interactions with specific cell surface receptors, the best characterized of which is the receptor for AGE (RAGE). Recent evidence suggests that the AGE-RAGE interaction may also be promoted by inflammatory processes and oxidative cellular injury. To characterize the distributions of AGE and RAGE in diabetic kidneys and to determine their specificity for diabetic nephropathy, an immunohistochemical analysis of renal biopsies from patients with diabetic nephropathy (n = 26), hypertensive nephrosclerosis (n = 7), idiopathic focal segmental glomerulosclerosis (n = 11), focal sclerosis secondary to obesity (n = 7), and lupus nephritis (n = 11) and from normal control subjects (n = 2) was performed, using affinity-purified antibodies raised to RAGE and two subclasses of AGE, i.e., N(epsilon)-(carboxymethyl)-lysine (CML) and pentosidine (PENT). AGE were detected equally in diffuse and nodular diabetic nephropathy. CML was the major AGE detected in diabetic mesangium (96%), glomerular basement membranes (GBM) (42%), tubular basement membranes (85%), and vessel walls (96%). In diabetic nephropathy, PENT was preferentially located in interstitial collagen (90%) and was less consistently observed in vessel walls (54%), mesangium (77%), GBM (4%), and tubular basement membranes (31%). RAGE was expressed on normal podocytes and was upregulated in diabetic nephropathy. The restriction of RAGE mRNA expression to glomeruli was confirmed by reverse transcription-PCR analysis of microdissected renal tissue compartments. The extent of mesangial and GBM immunoreactivity for CML, but not PENT, was correlated with the severity of diabetic glomerulosclerosis, as assessed pathologically. CML and PENT were also identified in areas of glomerulosclerosis and arteriosclerosis in idiopathic and secondary focal segmental glomerulosclerosis, hypertensive nephrosclerosis, and lupus nephritis. In active lupus nephritis, CML and PENT were detected in the proliferative glomerular tufts and crescents. In conclusion, CML is a major AGE in renal basement membranes in diabetic nephropathy, and its accumulation involves upregulation of RAGE on podocytes. AGE are also accumulated in acute inflammatory glomerulonephritis secondary to systemic lupus erythematosus, possibly via enzymatic oxidation of glomerular matrix proteins.
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PMID:Expression of advanced glycation end products and their cellular receptor RAGE in diabetic nephropathy and nondiabetic renal disease. 1096 90

Advanced glycation end products (AGEs) such as N(epsilon)-(carboxymethyl)lysine (CML) have been implicated in the development and progression of diabetic nephropathy. The aim of the present study is to investigate AGE levels in patients with type 2 diabetes with special regard to the role of renal impairment. Serum and urine CML levels (using a newly developed enzyme-linked immunosorbent assay), as well as serum AGE-fluorescence, were measured in 109 patients with type 2 diabetes. Patients were divided into groups with normal and impaired renal function. We found elevated serum fluorescent AGE and CML levels, as well as decreased urinary CML excretion rates, in patients with diabetes with renal impairment, but not those with normal renal function. In the presence of impaired renal function, serum CML and fluorescent AGE levels showed a significant inverse relation with creatinine clearance and a significant direct correlation with each other. No relationship could be found between serum AGE levels and parameters of blood glucose control or the presence of the following clinical complications: ischemic heart disease, diabetic retinopathy, and neuropathy. We conclude that the decline in renal function leads to increased serum AGE levels in patients with type 2 diabetes.
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PMID:N(epsilon)-(carboxymethyl)lysine levels in patients with type 2 diabetes: role of renal function. 1157 82

We investigated whether serum levels of N-(carboxymethyl)lysine (CML), non-CML advanced glycation endproducts (AGEs), or pentosidine are associated with severity of diabetic microvascular complications in patients with Type 1 diabetes. Serum levels of CML, non-CML AGE, and pentosidine were measured by an enzyme-linked immunosorbent assay in 38 males and 47 females aged 31+/-8 years (mean+/-S.D.) with Type 1 diabetes for 18.7+/-7.0 years. There was a significant correlation between serum levels of CML or non-CML AGE and current HbA(1c) level (P<.01 and P<.05, respectively). The serum levels of non-CML AGE, but not CML or pentosidine, were significantly increased as normal renal status advanced to microalbuminuria, clinical nephropathy, and hemodialysis (P<.0001) and were positively correlated with urinary albumin excretion (UAE) in patients with Type 1 diabetes (P<.0001). A significant elevation of serum non-CML AGE was found in association with the severity of diabetic retinopathy (P<.0001). We found in the present study that CML levels were also increased in the stage of simple retinopathy, the early stage of clinically evident retinopathy (P<.05). Serum levels of non-CML AGE were significantly associated with the severity of diabetic nephropathy and retinopathy, suggesting a role of non-CML AGE in the progression of microvascular complications in patients with Type 1 diabetes. Since serum levels of CML were significantly increased in patients with simple retinopathy, CML may participate in the initiation of diabetic retinopathy.
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PMID:Serum levels of non-carboxymethyllysine advanced glycation endproducts are correlated to severity of microvascular complications in patients with Type 1 diabetes. 1250 51

Advanced glycation end products (AGEs) from the Maillard reaction contribute to the pathogenesis of diabetes-associated complications such as diabetic nephropathy. In therapeutic interventions for reducing AGEs, many compounds have been reported as AGE inhibitors. The objective of the present study was to examine the effect of pyridoxamine (K-163), an AGE inhibitor, in type 2 diabetic KK-A(y)/Ta mice. KK-A(y)/Ta mice were given pyridoxamine (200 or 400 mg/kg per day) starting at 8 weeks of age for 12 weeks. They were divided into 3 groups as follows: pyridoxamine 200 mg/kg per day treatment group (n = 10), pyridoxamine 400 mg/kg per day treatment group (n = 10), and a tap water group as the control group (n = 20). The urinary albumin/creatinine ratio (ACR), body weight (BW), levels of fasting and casual blood glucose, blood glycated hemoglobin (HbA(1c)), fasting serum insulin, triglyceride (TG), total cholesterol (T-Cho), and 3-deoxyglucosone (3DG), and systemic blood pressure were measured as biochemical parameters. N(epsilon)-(Carboxymethyl)lysine (CML) and nitrotyrosine accumulations in glomeruli were evaluated by immunohistochemical analyses. Transforming growth factor beta1 (TGF-beta1) and laminin-beta1 messenger RNA expressions in the kidneys were evaluated by real-time polymerase chain reaction. Pyridoxamine, especially at 400 mg/kg per day, improved the levels of urinary ACR, fasting serum TG, and 3DG. CML and nitrotyrosine accumulations in glomeruli were decreased. Furthermore, large doses of pyridoxamine prevented not only urinary ACR but also increases of BW, casual blood glucose, and HbA(1c). TGF-beta1 and laminin-beta1 messenger RNA expressions in kidneys were significantly lower than those in the controls. There were no significant changes in the levels of fasting blood glucose, serum T-Cho, and systemic blood pressure among all groups. It appears that pyridoxamine improved urinary ACR by its anti-AGE and anti-oxidant effects in the kidneys of KK-A(y)/Ta mice.
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PMID:Effect of pyridoxamine (K-163), an inhibitor of advanced glycation end products, on type 2 diabetic nephropathy in KK-A(y)/Ta mice. 1722 27

Renin angiotensin system (RAS) worsens diabetic nephropathy (DN) by increasing oxidative stress. We compared the effect of three different RAS inhibitors: the angiotensin converting enzyme inhibitor Ramipril, the vasopeptidase inhibitor AVE7688 and the angiotensin receptor (AT1) antagonist Losartan on the formation of oxidative and carbonyl stress derived protein modifications in kidney from Zucker obese hyperglycemic rats (ZDFn Gm-fa/fa). Gas chromatography-mass spectrometry was used to measure representative markers of several protein oxidative pathways: direct oxidation [dinitrophenylhydrazine reactive carbonyls (DNP), glutamic (GSA), and aminoadipic (AASA) semialdehydes], mixed glyco- and lipoxidation [N(epsilon)-carboxyethyl-lysine (CEL) and N(epsilon)-(carboxymethyl)-lysine (CML)] and lipoxidation-[N(epsilon)-(malondialdehyde)-lysine-(MDAL)], as well as renal fatty acid composition. Urinary albumin (a marker of DN), DNP, GSA, and MDAL levels, were increased in all obese rats and were dose dependently decreased by AVE7688 whereas Ramipril and Losartan were less efficient. These results show that RAS inhibition improves DN at several levels, independently of its effects on blood pressure and glycemic control, via mechanisms depending of renal oxidative stress.
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PMID:Inhibition of renin angiotensin system decreases renal protein oxidative damage in diabetic rats. 1824 27

Advanced glycation end products (AGEs) may play a role in the pathogenesis of diabetic nephropathy, by modulating extracellular matrix turnover. AGEs are known to activate specific membrane receptors, including the receptor for AGE (RAGE). In the present study, we analyzed the various receptors for AGEs expressed by human mesangial cells and we studied the effects of glycated albumin and of carboxymethyl lysine on matrix protein and remodelling enzyme synthesis. Membrane RAGE expression was confirmed by FACS analysis. Microarray methods, RT-PCR, and Northern blot analysis were used to detect and confirm specific gene induction. Zymographic analysis and ELISA were used to measure the induction of tPA and PAI-1. We show herein that cultured human mesangial cells express AGE receptor type 1, type 2 and type 3 and RAGE. AGEs (200 microg/ml) induced at least a 2-fold increase in mRNA for 10 genes involved in ECM remodelling, including tPA, PAI-1 and TIMP-3. The increase in tPA synthesis was confirmed by fibrin zymography. The stimulation of PAI-1 synthesis was confirmed by ELISA. AGEs increased PAI-1 mRNA through a signalling pathway involving reactive oxygen species, the MAP kinases ERK-1/ERK-2 and the nuclear transcription factor NF-kappaB, but not AP-1. Carboxymethyl lysine (CML, 5 microM), which is a RAGE ligand, also stimulated PAI-1 synthesis by mesangial cells. In addition, a blocking anti-RAGE antibody partially inhibited the AGE-stimulated gene expression and decreased the PAI-1 accumulation induced by AGEs and by CML. Inhibition of AGE receptors or neutralization of the protease inhibitors TIMP-3 and PAI-1 could represent an important new therapeutic strategy for diabetic nephropathy.
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PMID:Advanced glycation end products regulate extracellular matrix protein and protease expression by human glomerular mesangial cells. 1928 28


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