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Sample records for advanced glycation endproducts

  1. Dietary advanced glycation endproducts

    DEFF Research Database (Denmark)

    Poulsen, Malene Wibe

    High heat cooking induces flavor, aroma, and color of food, but leads to formation of advanced glycation endproducts (AGEs) by the Maillard reaction. In addition to the formation in food, AGEs are also formed in vivo, and increased endogenous formation of AGEs has been linked to diabetic...... for biological effects of high heat-treated diets in humans. Studies with well-defined AGEs should be undertaken in order to advance our understanding of biological effects of specific AGEs....... sensitivity of cooking methods that induce or limit AGE formation were investigated in healthy overweight women. It was concluded that insulin sensitivity was improved with use of low heat cooking methods, compared with high heat cooking methods. In a rat study, effects on expression of AGE receptors, insulin...

  2. Advanced glycation endproducts in chronic heart failure

    NARCIS (Netherlands)

    Smit, Andries J.; Hartog, Jasper W. L.; Voors, Adriaan A.; van Veldhuisen, Dirk J.; Schleicher, E; Somoza,; Shieberle, P

    2008-01-01

    Advanced glycation endproducts (AGEs) have been proposed as factors involved in the development and progression of chronic heart failure (CHF). Cross-linking by AGEs results in vascular and myocardial stiffening, which are hallmarks in the pathogenesis of CHE Additionally, stimulation of receptors b

  3. Methylglyoxal-Derived Advanced Glycation Endproducts in Multiple Sclerosis

    Science.gov (United States)

    Wetzels, Suzan; Wouters, Kristiaan; Schalkwijk, Casper G.; Vanmierlo, Tim; Hendriks, Jerome J. A.

    2017-01-01

    Multiple sclerosis (MS) is a demyelinating disease of the central nervous system (CNS). The activation of inflammatory cells is crucial for the development of MS and is shown to induce intracellular glycolytic metabolism in pro-inflammatory microglia and macrophages, as well as CNS-resident astrocytes. Advanced glycation endproducts (AGEs) are stable endproducts formed by a reaction of the dicarbonyl compounds methylglyoxal (MGO) and glyoxal (GO) with amino acids in proteins, during glycolysis. This suggests that, in MS, MGO-derived AGEs are formed in glycolysis-driven cells. MGO and MGO-derived AGEs can further activate inflammatory cells by binding to the receptor for advanced glycation endproducts (RAGE). Recent studies have revealed that AGEs are increased in the plasma and brain of MS patients. Therefore, AGEs might contribute to the inflammatory status in MS. Moreover, the main detoxification system of dicarbonyl compounds, the glyoxalase system, seems to be affected in MS patients, which may contribute to high MGO-derived AGE levels. Altogether, evidence is emerging for a contributing role of AGEs in the pathology of MS. In this review, we provide an overview of the current knowledge on the involvement of AGEs in MS. PMID:28212304

  4. Advanced glycation endproducts in food and their effects on health

    DEFF Research Database (Denmark)

    Poulsen, Malene Wibe; Hedegaard, Rikke Susanne Vingborg; Andersen, Jeanette Marker

    2013-01-01

    Advanced glycation endproducts (AGEs) form by Maillard-reactions after initial binding of aldehydes with amines or amides in heated foods or in living organisms. The mechanisms of formation may include ionic as well as oxidative and radical pathways. The reactions may proceed within proteins...... of AGEs. Some AGEs interact with specific pro- or anti-inflammatory receptors. Most studies on the biological effects of AGEs have been carried out by administering heated foods. The pro-inflammatory and deteriorating biological effects of AGEs in these studies, therefore, need further confirmation...

  5. Advanced glycation end-products inhibitors isolated from Schisandra grandiflora.

    Science.gov (United States)

    Poornima, B; Kumar, D Anand; Siva, Bandi; Venkanna, A; Vadaparthi, P R Rao; Kumar, K; Tiwari, Ashok K; Babu, K Suresh

    2016-01-01

    Free radicals scavenging and advanced glycation end-products (AGEs) inhibitory potentials in crude chloroform extract of Schisandra grandiflora were evaluated. Bioassay-guided isolation of the chloroform extract led to the identification of 24 compounds. Among the isolates, ( ± ) gomisin M1, arisantetralone C and D, macelignan, saurulignan B and SZ-MO displayed potent-free radical scavenging as well as AGEs inhibitory potentials. This is the first report identifying the presence of AGEs inhibitory activity and assigning AGEs inhibitory activity to these compounds. Therefore, our research finds new application of traditional medicinal plant S. grandiflora having capacity to reduce formation and accumulation of AGEs in diabetes.

  6. Clinical relevance of advanced glycation endproducts for vascular surgery.

    Science.gov (United States)

    Meerwaldt, R; van der Vaart, M G; van Dam, G M; Tio, R A; Hillebrands, J-L; Smit, A J; Zeebregts, C J

    2008-08-01

    Atherosclerosis is the main contributor to cardiovascular disease and leads to intimal plaque formation, which may progress to plaque rupture with subsequent thromboembolic events and/or occlusion of the arterial lumen. There is increasing evidence that the development or progression of atherosclerosis is associated with advanced glycation endproducts (AGEs). AGEs are a heterogeneous group of compounds formed by the non-enzymatic reaction of reducing sugars with proteins, lipids, and nucleic acids. An increased understanding of the mechanisms of formation and interaction of AGEs has allowed the development of several potential anti-AGE strategies. This review summarizes AGE formation and biochemistry, the pathogeneic role of AGEs in cardiovascular disease, anti-AGE therapies and clinical relevance to vascular surgery.

  7. Advanced glycation endproducts in horses with insulin-induced laminitis.

    Science.gov (United States)

    de Laat, M A; Kyaw-Tanner, M T; Sillence, M N; McGowan, C M; Pollitt, C C

    2012-01-15

    Advanced glycation endproducts (AGEs) have been implicated in the pathogenesis of cancer, inflammatory conditions and diabetic complications. An interaction of AGEs with their receptor (RAGE) results in increased release of pro-inflammatory cytokines and reactive oxygen species (ROS), causing damage to susceptible tissues. Laminitis, a debilitating foot condition of horses, occurs in association with endocrine dysfunction and the potential involvement of AGE and RAGE in the pathogenesis of the disease has not been previously investigated. Glucose transport in lamellar tissue is thought to be largely insulin-independent (GLUT-1), which may make the lamellae susceptible to protein glycosylation and oxidative stress during periods of increased glucose metabolism. Archived lamellar tissue from horses with insulin-induced laminitis (n=4), normal control horses (n=4) and horses in the developmental stages (6h, 12h and 24h) of the disease (n=12) was assessed for AGE accumulation and the presence of oxidative protein damage and cellular lipid peroxidation. The equine-specific RAGE gene was identified in lamellar tissue, sequenced and is now available on GenBank. Lamellar glucose transporter (GLUT-1 and GLUT-4) gene expression was assessed quantitatively with qRT-PCR in laminitic and control horses and horses in the mid-developmental time-point (24 h) of the disease. Significant AGE accumulation had occurred by the onset of insulin-induced laminitis (48 h) but not at earlier time-points, or in control horses. Evidence of oxidative stress was not found in any group. The equine-specific RAGE gene was not expressed differently in treated and control animals, nor was the insulin-dependent glucose transporter GLUT-4. However, the glucose transporter GLUT-1 was increased in lamellar tissue in the developmental stages of insulin-induced laminitis compared to control horses and the insulin-independent nature of the lamellae may facilitate AGE formation. However, due to the lack of

  8. Advanced glycation end-products, a pathophysiological pathway in the cardiorenal syndrome

    NARCIS (Netherlands)

    Willemsen, Suzan; Hartog, Jasper W. L.; Heiner-Fokkema, Rebecca; van Veldhuisen, Dirk J.; Voors, Adriaan A.

    2012-01-01

    The prevalence of heart failure (HF) is increasing. A distinction is made between diastolic HF (preserved left ventricular ejection fraction (LVEF)) and systolic HF (reduced LVEF). Advanced glycation end-products (AGEs) are crystallized proteins that accumulate during ageing, but are particularly in

  9. Effects of advanced glycation end-product inhibition and cross-link breakage in diabetic rats

    DEFF Research Database (Denmark)

    Oturai, P S; Christensen, M; Rolin, B

    2000-01-01

    The accelerated formation of advanced glycation end-products (AGEs) due to elevated glycemia has repeatedly been reported as a central pathogenic factor in the development of diabetic microvascular complications. The effects of a novel inhibitor of AGE formation, NNC39-0028 (2,3-diaminophenazine...

  10. The clinical relevance of advanced glycation endproducts (AGE) and recent developments in pharmaceutics to reduce AGE accumulation

    NARCIS (Netherlands)

    Smit, AJ; Lutgers, HL

    2004-01-01

    Advanced glycation endproducts (AGE) are a class of compounds resulting from glycation and oxidation of proteins, lipids or nucleic acids. Glycation is the non-enzymatic addition or insertion of saccharide derivatives to these molecules. This leads to the formation of intermediary Schiff bases and A

  11. Pomegranate phenolics inhibit formation of advanced glycation endproducts by scavenging reactive carbonyl species.

    Science.gov (United States)

    Liu, Weixi; Ma, Hang; Frost, Leslie; Yuan, Tao; Dain, Joel A; Seeram, Navindra P

    2014-11-01

    Advanced Glycation Endproducts (AGEs) are a heterogeneous group of molecules produced from non-enzymatic glycation. Accumulation of AGEs in vivo plays an important role in the pathology of chronic human diseases including type-2 diabetes and Alzheimer's disease. Natural AGEs inhibitors such as the pomegranate (Punica granatum) fruit show great potential for the management of these diseases. Herein, we investigated the in vitro anti-glycation effects of a pomegranate fruit extract (PE), its phenolic constituents [punicalagin (PA), ellagic acid (EA) and gallic acid (GA)], and their in vivo derived colonic metabolites [urolithin A (UA) and urolithin B (UB)]. All of the samples showed anti-glycation activities and PE, PA, and EA were more potent inhibitors than the positive control, aminoguanidine. PE and the purified phenolics also exhibited carbonyl scavenger reactivity. Our study suggests that pomegranate may offer an attractive dietary strategy for the prevention and treatment of AGE-related diseases such as type-2 diabetes and Alzheimer's disease.

  12. Linolenic acid prevents early and advanced glycation end-products (AGEs) modification of albumin.

    Science.gov (United States)

    Prasanna, Govindarajan; Saraswathi, N T

    2017-02-01

    In this study, we report the protective effects of linolenic acid towards the formation of early (HbA1c) and advanced glycation end-products (AGEs) based on fluorescence, circular dichroism, confocal microscopy and molecular interaction studies. Linolenic acid was found to be a potent inhibitor of AGEs formed by both glucose and fructose. The HbA1c (early glycation product) level was found to be reduced to 7.4% when compared to glycated control (8.4%). Similarly, linolenic acid also inhibited the methylglyoxal mediated AGEs formation. Circular dichroism spectroscopy studies suggested that the protective effect of linolenic acid for the helical structure of albumin. The molecular interaction studies showed that linolenic acid interacts with arginine residues of albumin with high affinity. Results suggested linolenic acid to be a potent antiglycation compound and also it could be a better lead compound for AGE inhibition.

  13. A novel advanced glycation endproducts breaker restores cardiovascular dysfunctions in experimental diabetic rats

    Institute of Scientific and Technical Information of China (English)

    GangCHENG; Li-liWANG; Hong-yingLIU; HaoCUI; Ying-linCAO; SongLI

    2005-01-01

    AIM The formation of advanced glycation endproducts (AGEs) on connective tissue and matrix components leads to increases in collagen crosslinkingthat contributes to aortic and myocardial stiffness in normal aging and which occurs at an accelerated rate in diabetes. In this study, we examined the effects of a novel AGEs breaker, C36, on cardiovascular dysfunctions in experimental diabetic rats. METHODS and RESULTS Male Wiatar rats were made diabetic by i.p. injection of 70mg/kg streptozotocin. After 12 weeks of diabetes, the animals were randomly divided into 4 groups (n=8-11),

  14. The clinical relevance of assessing advanced glycation endproducts accumulation in diabetes.

    Science.gov (United States)

    Meerwaldt, Robbert; Links, Thera; Zeebregts, Clark; Tio, Rene; Hillebrands, Jan-Luuk; Smit, Andries

    2008-10-07

    Cardiovascular disease is the major cause of morbidity and mortality associated with diabetes. There is increasing evidence that advanced glycation endproducts (AGEs) play a pivotal role in atherosclerosis, in particular in diabetes. AGE accumulation is a measure of cumulative metabolic and oxidative stress, and may so represent the "metabolic memory". Furthermore, increased AGE accumulation is closely related to the development of cardiovascular complications in diabetes. This review article will focus on the clinical relevance of measuring AGE accumulation in diabetic patients by focusing on AGE formation, AGEs as predictors of long-term complications, and interventions against AGEs.

  15. The clinical relevance of assessing advanced glycation endproducts accumulation in diabetes

    Directory of Open Access Journals (Sweden)

    Hillebrands Jan-Luuk

    2008-10-01

    Full Text Available Abstract Cardiovascular disease is the major cause of morbidity and mortality associated with diabetes. There is increasing evidence that advanced glycation endproducts (AGEs play a pivotal role in atherosclerosis, in particular in diabetes. AGE accumulation is a measure of cumulative metabolic and oxidative stress, and may so represent the "metabolic memory". Furthermore, increased AGE accumulation is closely related to the development of cardiovascular complications in diabetes. This review article will focus on the clinical relevance of measuring AGE accumulation in diabetic patients by focusing on AGE formation, AGEs as predictors of long-term complications, and interventions against AGEs.

  16. Screening system of blocking agents of the receptor for advanced glycation endproducts in cells using fluorescence.

    Science.gov (United States)

    Jung, Dong Ho; Kim, Young Sook; Kim, Jin Sook

    2012-01-01

    Activation of the receptor for advanced glycation endproducts (RAGE) triggers cellular responses implicated in the pathogenesis of diabetic complications; blockade of RAGE has been shown to inhibit the development of diabetic complications. To develop a screening system to identify novel disruptors of advanced glycation endproducts (AGE)-RAGE binding, we used an AGE-RAGE binding system in RAGE-overexpressing cells; test compounds were screened using this system. To construct human RAGE-overexpressing cells, mouse mesangial cells (MMCs) were stably transfected with the pcDNA-human RAGE (hRAGE) vector and selected under 1 mg/mL gentamicin (G418). RAGE expression in hRAGE-overexpressing MMCs was analyzed by Western blotting with specific RAGE antibody. To identify novel disruptors of AGE-RAGE binding, 50 single compounds and AGE-bovine serum albumin (BSA)-Alexa 488 (AGE-BSA labeled with Alexa 488) were treated to the hRAGE-overexpressing MMCs. Nonbinding AGE-BSA-Alexa 488 was washed and fluorescence measured by microtiter plate reader (excitation wavelength, 485 nm; emission wavelength, 528 nm). In hRAGE-overexpressing cells, only treatment with AGE-BSA-Alexa 488 significantly increased fluorescence intensity in a dose-dependent manner. Of 50 compounds tested, genistein disrupted AGE-RAGE binding in a dose-dependent manner. This AGE-RAGE binding system using AGE-BSA-Alexa 488 in hRAGE-overexpressing cells was suitable for screening of agents that disrupt AGE-hRAGE binding.

  17. Advanced glycation end-products, anti-hypertensive treatment and diastolic function in patients with hypertension and diastolic dysfunction

    NARCIS (Netherlands)

    Hartog, Jasper W. L.; van de Wal, Ruud M.; Schalkwijk, Casper G.; Miyata, Toshio; Jaarsma, Wybren; Plokker, H. W. Thijs; van Wijk, Leen M.; Smit, Andries J.; van Veldhuisen, Dirk J.; Voors, Adriaan A.

    2010-01-01

    Aims To investigate the relationship between advanced glycation end-products (AGEs) and diastolic function and the response to blood pressure treatment in patients with hypertension and diastolic dysfunction. Methods and results Data were analysed from 97 patients (aged 65 +/- 10 years, 36% male) wh

  18. Effects of combined lipoic acid and pyridoxine on albuminuria, advanced glycation end-products, and blood pressure in diabetic nephropathy.

    Science.gov (United States)

    Noori, Nazanin; Tabibi, Hadi; Hosseinpanah, Farhad; Hedayati, Mehdi; Nafar, Mohsen

    2013-01-01

    This study was designed to investigate the effects of combined administration of lipoic acid and pyridoxine on albuminuria, oxidative stress, blood pressure, serum advanced glycation end-products, nitric oxide (NO), and endothelin-1 in patients with diabetic nephropathy. Thirty-four patients were randomly assigned to either a supplement group or a placebo group. The patients in the supplement group received 800 mg lipoic acid and 80 mg pyridoxine daily for 12 weeks, whereas the placebo group received corresponding placebos. Urinary albumin, serum malondialdehyde (MDA), and systolic blood pressure decreased significantly in the supplement group compared to the placebo group (p blood pressure. The present study indicates that combined administration of lipoic acid and pyridoxine improves albuminuria in patients with diabetic nephropathy by reducing oxidative stress, advanced glycation end-products, and systolic blood pressure. The reduction in microalbuminuria may be of benefit in retarding the progression of diabetic nephropathy.

  19. Aging induces cardiac diastolic dysfunction, oxidative stress, accumulation of advanced glycation endproducts and protein modification.

    Science.gov (United States)

    Li, Shi-Yan; Du, Min; Dolence, E Kurt; Fang, Cindy X; Mayer, Gabriele E; Ceylan-Isik, Asli F; LaCour, Karissa H; Yang, Xiaoping; Wilbert, Christopher J; Sreejayan, Nair; Ren, Jun

    2005-04-01

    Evidence suggests that aging, per se, is a major risk factor for cardiac dysfunction. Oxidative modification of cardiac proteins by non-enzymatic glycation, i.e. advanced glycation endproducts (AGEs), has been implicated as a causal factor in the aging process. This study was designed to examine the role of aging on cardiomyocyte contractile function, cardiac protein oxidation and oxidative modification. Mechanical properties were evaluated in ventricular myocytes from young (2-month) and aged (24-26-month) mice using a MyoCam system. The mechanical indices evaluated were peak shortening (PS), time-to-PS (TPS), time-to-90% relengthening (TR90) and maximal velocity of shortening/relengthening (+/- dL/dt). Oxidative stress and protein damage were evaluated by glutathione and glutathione disulfide (GSH/GSSG) ratio and protein carbonyl content, respectively. Activation of NAD(P)H oxidase was determined by immunoblotting. Aged myocytes displayed a larger cell cross-sectional area, prolonged TR90, and normal PS, +/- dL/dt and TPS compared with young myocytes. Aged myocytes were less tolerant of high stimulus frequency (from 0.1 to 5 Hz) compared with young myocytes. Oxidative stress and protein oxidative damage were both elevated in the aging group associated with significantly enhanced p47phox but not gp91phox expression. In addition, level of cardiac AGEs was approximately 2.5-fold higher in aged hearts than young ones determined by AGEs-ELISA. A group of proteins with a molecular range between 50 and 75 kDa with pI of 4-7 was distinctively modified in aged heart using one- or two-dimension SDS gel electrophoresis analysis. These data demonstrate cardiac diastolic dysfunction and reduced stress tolerance in aged cardiac myocytes, which may be associated with enhanced cardiac oxidative damage, level of AGEs and protein modification by AGEs.

  20. Collagen modifications in postmenopausal osteoporosis: advanced glycation endproducts may affect bone volume, structure and quality.

    Science.gov (United States)

    Willett, Thomas L; Pasquale, Julia; Grynpas, Marc D

    2014-09-01

    The classic model of postmenopausal osteoporosis (PM-OP) starts with the depletion of estrogen, which in turn stimulates imbalanced bone remodeling, resulting in loss of bone mass/volume. Clinically, this leads to fractures because of structural weakness. Recent work has begun to provide a more complete picture of the mechanisms of PM-OP involving oxidative stress and collagen modifications known as advanced glycation endproducts (AGEs). On one hand, AGEs may drive imbalanced bone remodeling through signaling mediated by the receptor for AGEs (RAGE), stimulating resorption and inhibiting formation. On the other hand, AGEs are associated with degraded bone material quality. Oxidative stress promotes the formation of AGEs, inhibits normal enzymatically derived crosslinking and can degrade collagen structure, thereby reducing fracture resistance. Notably, there are multiple positive feedback loops that can exacerbate the mechanisms of PM-OP associated with oxidative stress and AGEs. Anti-oxidant therapies may have the potential to inhibit the oxidative stress based mechanisms of this disease.

  1. Advanced glycation endproducts in 35 types of seafood products consumed in eastern China

    Science.gov (United States)

    Wang, Jing; Li, Zhenxing; Pavase, Ramesh Tushar; Lin, Hong; Zou, Long; Wen, Jie; Lv, Liangtao

    2016-08-01

    Advanced glycation endproducts (AGEs) have been recognized as hazards in processed foods that can induce chronic diseases such as cardiovascular disease, diabetes, and diabetic nephropathy. In this study, we investigated the AGEs contents of 35 types of industrial seafood products that are consumed frequently in eastern China. Total fluorescent AGEs level and Nɛ-carboxymethyl-lysine (CML) content were evaluated by fluorescence spectrophotometry and gas chromatography-mass spectrometry (GC-MS), respectively. The level of total fluorescent AGEs in seafood samples ranged from 39.37 to 1178.3 AU, and was higher in canned and packaged instant aquatic products that were processed at high temperatures. The CML content in seafood samples ranged from 44.8 to 439.1 mg per kg dried sample, and was higher in roasted seafood samples. The total fluorescent AGEs and CML content increased when seafood underwent high-temperature processing, but did not show an obvious correlation. The present study suggested that commonly consumed seafood contains different levels of AGEs, and the seafood processed at high temperatures always displays a high level of either AGEs or CML.

  2. Two new prenylflavonoids from Epimedii Herba and their inhibitory effects on advanced glycation end-products.

    Science.gov (United States)

    Nakashima, Keisuke; Miyashita, Hiroyuki; Yoshimitsu, Hitoshi; Fujiwara, Yukio; Nagai, Ryoji; Ikeda, Tsuyoshi

    2016-04-01

    Because inhibitors of advanced glycation end-products (AGEs), for example pyridoxamine, significantly inhibit the development of retinopathy and neuropathy in rats with streptozotocin-induced diabetes, treatment with AGE inhibitors is believed to be a potential strategy for the prevention of lifestyle-related diseases such as diabetic complications. In the present study, the MeOH extract of Epimedii Herba (EH; aerial parts of Epimedium spp.) was found to inhibit the formation of N (ε) -(carboxymethyl)lysine (CML) and N (ω) -(carboxymethyl)arginine (CMA) during incubation of collagen-derived gelatin with ribose. Furthermore, compounds with inhibitory effects against CML and CMA formation were isolated from EH. Two new prenylflavonoids (compounds 1 and 2) and two known compounds (3 and 4) were found to significantly inhibit the formation of both CML and CMA; compound 4 (epimedokoreanin B) had the strongest inhibitory effect of the isolated compounds. These data suggest that epimedokoreanin B could prevent clinical complications of diabetes by inhibiting AGEs.

  3. Chronic Spontaneous Urticaria Is Characterized by Lower Serum Advanced Glycation End-Products

    Directory of Open Access Journals (Sweden)

    Alicja Grzanka

    2014-01-01

    Full Text Available Background. Chronic spontaneous urticaria (CSU is associated with activation of acute phase response. On the other hand, it is known that systemic inflammation may lead to increased formation of advanced glycation end-products (AGEs, associated with pathogenesis of various diseases. Aim. We aim to test whether chronic inflammation manifested by activated acute phase response may provide a mechanism for increased serum AGEs concentration in CSU. Methods. Concentrations of AGEs were measured spectrofluorimetrically in serum of CSU patients and the healthy subjects. Results. Serum AGEs and albumin concentrations in CSU patients were significantly lower as compared with the healthy subjects. Serum CRP concentration was significantly higher in patients with CSU than in the controls. Significant positive correlation was observed between AGEs and albumin concentrations in the subjects. Conclusions. CSU is not associated with increased circulating AGEs concentrations, despite the enhanced systemic inflammatory response. Paradoxical decrease of serum AGEs concentrations is probably a reflection of lower concentration of “negative acute phase proteins” such as albumin.

  4. Global proteomic screening of protein allergens and advanced glycation endproducts in thermally processed peanuts.

    Science.gov (United States)

    Hebling, Christine M; McFarland, Melinda A; Callahan, John H; Ross, Mark M

    2013-06-19

    Peanuts (Arachis hypogaea) are the cause of one of the most prevalent food allergies worldwide. Thermal processing (e.g., roasting) of peanuts and peanut-containing foods results in complex chemical reactions that alter structural conformations of peanut proteins, preventing accurate detection of allergens by most immunochemical and targeted screening methodologies. To improve food allergen detection and support more accurate food labeling, traditional methods for peanut protein extraction were modified to include protein denaturants and solubilization agents. Qualitative characterization by SDS-PAGE and Western blot analyses of raw and variably roasted peanut extracts confirmed improvements in total protein recovery and provided evidence for the incorporation of Ara h 1, Ara h 3, and, to a lesser extent, Ara h 2 into high molecular weight protein complexes upon roasting. Relative quantification of allergens in peanut lysates was accomplished by label-free spectral feature (MS1) LC-MS/MS methodologies, by which peanut allergen peptides exhibiting a differential MS response in raw versus roasted peanuts were considered to be candidate targets of thermal modification. Identification of lysine-modified Maillard advanced glycation endproducts (AGE) by LC-MS/MS confirmed the formation of (carboxymethyl)lysine (CML), (carboxyethyl)lysine (CEL), and pyrraline (Pyr) protein modifications on Ara h 1 and Ara h 3 tryptic peptides in roasted peanut varieties. These results suggest that complex processed food matrices require initial analysis by an untargeted LC-MS/MS approach to determine optimum analytes for subsequent targeted allergen analyses.

  5. Retinol up-regulates the receptor for advanced glycation endproducts (RAGE) by increasing intracellular reactive species.

    Science.gov (United States)

    Gelain, Daniel Pens; de Bittencourt Pasquali, Matheus Augusto; Caregnato, Fernanda Freitas; Zanotto-Filho, Alfeu; Moreira, José Cláudio Fonseca

    2008-08-01

    Retinol (vitamin A) and other retinoids have been suggested to exert an important antioxidant function in biological systems, besides their more established role as regulators of cell growth and differentiation. On the other hand, many authors have recently observed pro-oxidant activities of vitamin A and other retinoids in vitro and in vivo, resulting in cell death and/or transformation associated to increased oxidative damage. However, the mechanisms by which retinol causes oxidative stress are still not fully understood. Receptors for advanced glycation endproducts (RAGE) have been recently implied as promoters and/or amplifiers of oxidant-mediated cell death induced by diverse agents, and increased RAGE expression is observed in conditions related to unbalanced production of reactive species, such as in atherosclerosis and neurodegeneration. In the present work, we observed that retinol supplementation increases RAGE protein expression in cultured Sertoli cells, and antioxidant co-treatment reversed this effect. Retinol-increased RAGE expression was observed only at concentrations that induce intracellular reactive species production, as assessed by the DCFH assay. These results indicate that retinol is able to increase RAGE expression by an oxidant-dependent mechanism, and suggest that RAGE signaling may be involved in some of the deleterious effects observed in some retinol-supplementation therapies.

  6. Influence of tonifying kidney recipe on advanced glycation endproducts and lipid peroxidation in ova riectomized rats

    Institute of Scientific and Technical Information of China (English)

    Yuefen Wang; Chang'an Zhao; Li Guo; En Li

    2008-01-01

    BACKGROUND:Previous studies have demonstrated that reduced estrogen levels may accelerate the formation of advanced glycation endproducts(AGE)in brain tissue,raise the concentration of lipid peroxidation products in vivo,and speed up deterioration of learning and memory.A tonifying kidney recipe is hypothesized to improve the ability of learning and memory in ovariectomized rats by downregulating AGE and lipid peroxidation products.OBJECTIVE:To simulate a postmenopausal state,bilateral ovariectomy (OVX)was performed in rats,and the effects of tonifying kidney recipe(TKR)on AGE and lipid peroxidation in the rat cerebral cortex,hippocampus,and blood serum levels was measured.In addition,the effects on learning and memory were evaluated,and the effect of AGE-specific inhibitor aminoguanidine(AG)was compared with TKR.DESIGN,TIME AND SETTING:A randomized,in vivo,control experiment was performed at the scientific research center(Provincial Key Laboratory)in the Fourth Hospital of Hebei Medical University (Shjiiazhuang,Hebei Province,China)from May 2005 to January 2007.MATERIALS:Forty healthy,adult,female,Sprague Dawley rats were used for this study.TKR was composed of prepared rehmannia rhizome,epimedium herb,desert-living cistanche,and Szechwan lovage rhizome,which were provided by Shijiazhuang Medical Materials Company(China).A TKR extraction was prepared for further use.AG was provided by Sigma (USA).Forty rats were randomly divided into four groups:sham,OVX,AG and TKR,with 10 rats in each group.METHODS:The rat ovaries were resected in the OVX,AG and TKR groups,whereas the same volume of fat was resected in the sham group.At four weeks after OVX,the AG group received 1% AG water solution by lavage;the TKR group was administrated by lavage once per day at a dose of 6.3 g (crude drug)/kg;OVX and sham groups received equal volumes of tap water.MAIN OUTCOME MEASURES:Learning and memory behavior of rats was tested in a Y-electric maze 16 weeks after the OVX procedure

  7. C16, a novel advanced glycation endproduct breaker, restores cardiovascular dysfunction in experimental diabetic rats

    Institute of Scientific and Technical Information of China (English)

    Gang CHENG; Li-li WANG; Wen-sheng QU; Long LONG; Hao CUI; Hong-ying LIU; Ying-lin CAO; Song LI

    2005-01-01

    Aim: Advanced glycation endproducts (AGE) have been implicated in the pathogenesis of diabetic complications, including diabetic cardiovascular dysfunction.3-[2-(4-Bromo-phenyl)- 1-methyl-2-oxo-ethyl]-4,5,6,7-tetrahydro-benzothiazol-3-ium bromide (C16), a novel AGE breaker, was investigated for its effects on the development of cardiovascular disease in diabetic rats. Methods: Rats that had streptozotocin-induced diabetes for 12 weeks were divided into groups receiving C16 or vehicle by gavage. Results: In hemodynamic studies of the left ventricle,C16 treatment (25 or 50 mg/kg) for 4 weeks resulted in a significant increase in left ventricular systolic pressure, +dp/dtmax, and -dp/dtmax as compared with vehicletreated diabetic rats. Furthermore, in hemodynamic studies of the cardiovascular system, C16 (12.5, 25, or 50 mg/kg) treatment for 4 weeks resulted in a dosedependent and significant increase in cardiac output, a reduction of total peripheral resistance, and an increase in systemic arterial compliance when compared with vehicle-treated diabetic rats. Biochemical studies showed that C16 treatment also resulted in a significant decrease in immunoglobulin G-red blood cell surface crosslink content and an increase in collagen solubility. Morphological and immunohistochemical examinations indicated that C 16 was able to prevent increases of the collagen type Ⅲ/Ⅰ ratio in the aorta and decrease the accumulation of AGE in the aorta. Conclusion: C16 has the ability to reduce AGE accumulation in tissues in vivo, and can restore diabetes-associated cardiovascular disorders in rats. This provides a potential therapeutic approach for cardiovascular disease associated with diabetes and aging in humans.

  8. Inhibition of advanced glycation endproducts formation by Korean thistle,Cirsium maackii

    Institute of Scientific and Technical Information of China (English)

    Hyun Ah Jung; Jin Ju Park; Byung Sun Min; Hee Jin Jung; Md Nurul Islam; Jae Sue Choi

    2015-01-01

    Objective:To evaluate inhibitory potential of sevenKorean thistles against the advanced glycation endproducts(AGE) formation as well as to identify responsible compounds from the most active species.Methods:We used anin vitroAGE inhibition assay to evaluate the anti-diabetic complication potential of the methanol extracts of the selectedKorean thistles.Results:Among the sevenKorean thistles, the leaves ofCirsium maackii(C. maackii) exhibited the most significant inhibitory activity againstAGE formation.By means of bioassay-directed fractionation, a lignan, chlorogenic acid and14 flavonoids were isolated from the active ethyl acetate soluble fraction of a methanol extract fromC. maackii leaves.Luteolin and its5-O-glucoside have been previously isolated; however, a lignan and13 known compounds were isolated for the first time fromC. maackiileaves in this study.Most of the isolated compounds exhibited inhibitory activities against potentialAGE formation.Among them, cernuoside was shown to be the most potentAGE inhibitor with anIC50 value of21.21 μmol/L.Most importantly, two major flavonoids, luteolin and its5-O-glucoside, also significantly inhibitedAGE formation, withIC50 values of 36.33 and37.47 μmol/L, respectively.Structure activity relationship revealed that the presence of free3' and4' dihydroxyl group in flavonoids skeleton played an important role inAGE inhibition. Conclusions:These results indicate thatC. maackii andC. maackii-derived flavonoids might be explored further to develop therapeutic agents for the prevention of diabetic complications due to their significant inhibitory activity againstAGE formation.

  9. Clinical Value of High Mobility Group Box 1 and the Receptor for Advanced Glycation End-products in Head and Neck Cancer: A Systematic Review.

    Science.gov (United States)

    Nguyen, Austin; Bhavsar, Sheila; Riley, Erinn; Caponetti, Gabriel; Agrawal, Devendra

    2016-10-01

    Introduction High mobility group box 1 is a versatile protein involved in gene transcription, extracellular signaling, and response to inflammation. Extracellularly, high mobility group box 1 binds to several receptors, notably the receptor for advanced glycation end-products. Expression of high mobility group box 1 and the receptor for advanced glycation end-products has been described in many cancers. Objectives To systematically review the available literature using PubMed and Web of Science to evaluate the clinical value of high mobility group box 1 and the receptor for advanced glycation end-products in head and neck squamous cell carcinomas. Data synthesis A total of eleven studies were included in this review. High mobility group box 1 overexpression is associated with poor prognosis and many clinical and pathological characteristics of head and neck squamous cell carcinomas patients. Additionally, the receptor for advanced glycation end-products demonstrates potential value as a clinical indicator of tumor angiogenesis and advanced staging. In diagnosis, high mobility group box 1 demonstrates low sensitivity. Conclusion High mobility group box 1 and the receptor for advanced glycation end-products are associated with clinical and pathological characteristics of head and neck squamous cell carcinomas. Further investigation of the prognostic and diagnostic value of these molecules is warranted.

  10. Clinical Value of High Mobility Group Box 1 and the Receptor for Advanced Glycation End-products in Head and Neck Cancer: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Nguyen, Austin

    2016-04-01

    Full Text Available Introduction High mobility group box 1 is a versatile protein involved in gene transcription, extracellular signaling, and response to inflammation. Extracellularly, high mobility group box 1 binds to several receptors, notably the receptor for advanced glycation end-products. Expression of high mobility group box 1 and the receptor for advanced glycation end-products has been described in many cancers. Objectives To systematically review the available literature using PubMed and Web of Science to evaluate the clinical value of high mobility group box 1 and the receptor for advanced glycation end-products in head and neck squamous cell carcinomas. Data synthesis A total of eleven studies were included in this review. High mobility group box 1 overexpression is associated with poor prognosis and many clinical and pathological characteristics of head and neck squamous cell carcinomas patients. Additionally, the receptor for advanced glycation end-products demonstrates potential value as a clinical indicator of tumor angiogenesis and advanced staging. In diagnosis, high mobility group box 1 demonstrates low sensitivity. Conclusion High mobility group box 1 and the receptor for advanced glycation end-products are associated with clinical and pathological characteristics of head and neck squamous cell carcinomas. Further investigation of the prognostic and diagnostic value of these molecules is warranted.

  11. Skin Autofluorescence Relates to Soluble Receptor for Advanced Glycation End-Products and Albuminuria in Diabetes Mellitus

    OpenAIRE

    Šoupal, J.; G. Loni Ekali; Prázný, M.; Kalousová, M.; Kvasnička, J.; Landová, L.; Zima, T.; Škrha, J.

    2013-01-01

    The aim of this study was to compare skin autofluorescence caused by advanced glycation end-products (AGEs) with biochemical markers of endothelial dysfunction and soluble receptor for AGEs (sRAGE) in patients with diabetes. Skin autofluorescence (AF) assessed by AGE-Reader was evaluated with sRAGE and other biochemical parameters in 88 patients with diabetes (47 Type 1/T1DM/ and 41 Type 2/T2DM/) and 20 controls. Skin AF was significantly higher in T1DM and T2DM in comparison to controls (2.3...

  12. How Can Diet Affect the Accumulation of Advanced Glycation End-Products in the Human Body?

    Directory of Open Access Journals (Sweden)

    Axel Guilbaud

    2016-12-01

    Full Text Available The accumulation of advanced glycation end products (AGEs is associated with the complications of diabetes, kidney disease, metabolic disorders and degenerative diseases. It is recognized that the pool of glycation products found in the human body comes not only from an endogenous formation, but also from a dietary exposure to exogenous AGEs. In recent years, the development of pharmacologically-active ingredients aimed at inhibiting endogenous glycation has not been successful. Since the accumulation of AGEs in the human body appears to be progressive throughout life, an early preventive action against glycation could be effective through dietary adjustments or supplementation with purified micronutrients. The present article provides an overview of current dietary strategies tested either in vitro, in vivo or both to reduce the endogenous formation of AGEs and to limit exposure to food AGEs.

  13. Increased expression of receptor for advanced glycation end-products worsens focal brain ischemia in diabetic rats

    Institute of Scientific and Technical Information of China (English)

    Ying Xing; Jinting He; Weidong Yu; Lingling Hou; Jiajun Chen

    2012-01-01

    A rat model of diabetes mellitus was induced by a high fat diet, followed by focal brain ischemia induced using the thread method after 0.5 month. Immunohistochemistry showed that expression of receptor for advanced glycation end-products was higher in the ischemic cortex of diabetic rats compared with non-diabetic rats with brain ischemia. Western blot assay revealed increased phosphorylated c-Jun N-terminal kinase expression, and unchanged phosphorylated extracellular signal-regulated protein kinase protein expression in the ischemic cortex of diabetic rats compared with non-diabetic rats with brain ischemia. Additionally, phosphorylated p38 mitogen-activated protein kinase protein was not detected in any rats in the two groups. Severity of limb hemiplegia was worse in diabetic rats with brain ischemia compared with ischemia alone rats. The results suggest that increased expression of receptor for advanced glycation end-products can further activate the c-Jun N-terminal kinase pathway in mitogen-activated protein kinase, thereby worsening brain injury associated with focal brain ischemia in diabetic rats.

  14. Skin-autofluorescence, a measure of tissue advanced glycation end-products (AGEs), is related to diastolic function in dialysis patients

    NARCIS (Netherlands)

    Hartog, Jasper W. L.; Hummel, Yoran M.; Voors, Adriaan A.; Schalkwijk, Casper G.; Miyata, Toshio; Huisman, Roel M.; Smit, Andries J.; Van Veldhuisen, Dirk J.

    2008-01-01

    Background: Diastolic dysfunction is a frequent cause of heart failure. particularly in dialysis patients. Advanced glycation endproducts (AGEs) are increased in dialysis patients and are suggested to play a role in the development of diastolic dysfunction. The aim of our study was to assess whether

  15. Skin autofluorescence, a novel marker for glycemic and oxidative stress-derived advanced glycation endproducts : An overview of current clinical studies, evidence, and limitations

    NARCIS (Netherlands)

    Mulder, Douwe J.; Van de Water, Tara; Lutgers, Helen L.; Graaff, Reindert; Gans, Rijk O.; Zijlstra, Felix; Smit, Andries J.

    2006-01-01

    Background: Advanced glycation endproducts (AGES) predict long-term complications in age-related diseases. However, there are no clinically applicable markers for measuring AGES in vivo. Methods: We have recently introduced the AGE-Reader (DiagnOptics B.V., Groningen, The Netherlands) to noninvasive

  16. Risk factors for chronic transplant dysfunction and cardiovascular disease are related to accumulation of advanced glycation end-products in renal transplant recipients

    NARCIS (Netherlands)

    Hartog, Jasper W. L.; de Vries, Aiko P. J.; Bakker, Stephan J. L.; Graaff, Reindert; van Son, Willem J.; van der Heide, Jaap J. Homan; Gans, Reinold O. B.; Wolffenbuttel, Bruce H. R.; de Jong, Paul E.; Smit, Andries J.

    2006-01-01

    Background. Accumulation of advanced glycation end-products (AGEs) has been implicated in the pathogenesis of chronic transplant dysfunction and cardiovascular disease in renal transplant recipients. We aimed to investigate which factors are associated with tissue AGE accumulation in renal transplan

  17. Advanced glycation end-product expression is upregulatedin the gastrointestinal tract of type 2 diabetic rats

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    AIM: To investigate changes in advanced glycation endproducts (AGEs) and their receptor (RAGE) expressionin the gastrointestinal (GI) tract in type 2 diabetic rats.METHODS: Eight inherited type 2 diabetic rats Goto-Kakizak (GK) and ten age-matched normal rats wereused in the study. From 18 wk of age, the body weightand blood glucose were measured every week and 2wk respectively. When the rats reached 32 wk, twocentimetersegments of esophagus, duodenum,jejunum, ileum, and colon were excised and the wetweight was measured. The segments were fixedin 10% formalin, embedded in paraffin and fivemicron sections were cut. The layer thickness wasmeasured in Hematoxylin and Eosin-stained slides.AGE [N epsilon-(carboxymethyl) lysine and N epsilon-(carboxyethyl)lysine] and RAGE were detected byimmunohistochemistry staining and image analysis wasdone using Sigmascan Pro 4.0 image analysis software.RESULTS: The blood glucose concentration (mmol/L)at 18 wk age was highest in the GK group (8.88 ±1.87 vs 6.90 ± 0.43, P 〈 0.001), a difference thatcontinued to exist until the end of the experiment.The wet weight per unit length (mg/cm) increased inesophagus, jejunum and colon from the normal to theGK group (60.64 ± 9.96 vs 68.56 ± 11.69, P 〈 0.05 foresophagus; 87.01 ± 9.35 vs 105.29 ± 15.45, P 〈 0.01for jejunum; 91.37 ± 7.25 vs 97.28 ± 10.90, P 〈 0.05for colon). Histologically, the layer thickness of the GI tract was higher for esophagus, jejunum and colon inthe GK group [full thickness (μm): 575.37 ± 69.22 vs753.20 ± 150.41, P 〈 0.01 for esophagus; 813.51 ±44.44 vs 884.81 ± 45.31, P 〈 0.05 for jejunum; 467.12± 65.92 vs 572.26 ± 93.60, P 〈 0.05 for colon]. Inesophagus, the AGE and RAGE mainly distributed instriated muscle cells and squamous epithelial cells. TheAGE distribution was much stronger in the GK groupcompared to the normal group both in the striatedmuscle layer and mucosa layer

  18. Singlet oxygen induced advanced glycation end-product photobleaching of in vivo human fingertip autofluorescence

    Science.gov (United States)

    Deng, Bin; Simental, Anabel; Lutz, Patrick; Shaheen, George; Chaiken, Joseph

    2012-01-01

    Nonenzymatic glycation and oxidation of ubiquitous proteins in vivo leads to irreversible formation of advanced glycation end products (AGEs). Due to their relatively long half life and low clearance rate AGEs tend to accumulate within static tissues and the circulatory system. Spectra obtained using 830 nm near-infrared (NIR) excitation suggest that the so-called "autofluorescence" from all tissues has a finite number of sources but the fact that senior and diabetic subjects produce more than other members of the general population suggests that a significant portion of the total autofluorescence from all sources originates from AGEs. Using pentosidine generated in a reaction mixture as described by Monnier as representative, an in vitro study unveiled very similar fluorescence and photobleaching pattern as observed for autofluorescence in vivo. A series of oxygen, air and argon purging experiments on the pentosidine-generating reaction mixture suggests that pentosidine is a singlet oxygen sensitizer and secondary reactions between the pentosidine itself and/or other fluorophores and the photosensitized singlet oxygen explain the observed photobleaching. Ab initio Gaussian calculations on pentosidine reveal the existence of low-lying triplet excited states required for the sensitization of ground state oxygen. A commercially available product known as singlet oxygen sensor green (SOSG) that specifically serves as a singlet oxygen detection reagent confirms the generation of singlet oxygen from NIR irradiated pentosidine trimixture. This study provides one definite chemical mechanism for understanding in vivo human skin autofluorescence and photobleaching.

  19. Advanced glycation End-products (AGEs): an emerging concern for processed food industries.

    Science.gov (United States)

    Sharma, Chetan; Kaur, Amarjeet; Thind, S S; Singh, Baljit; Raina, Shiveta

    2015-12-01

    The global food industry is expected to increase more than US $ 7 trillion by 2014. This rise in processed food sector shows that more and more people are diverging towards modern processed foods. As modern diets are largely heat processed, they are more prone to contain high levels of advanced glycation end products (AGEs). AGEs are a group of complex and heterogeneous compounds which are known as brown and fluorescent cross-linking substances such as pentosidine, non-fluorescent cross-linking products such as methylglyoxal-lysine dimers (MOLD), or non-fluorescent, non-cross linking adducts such as carboxymethyllysine (CML) and pyrraline (a pyrrole aldehyde). The chemistry of the AGEs formation, absorption and bioavailability and their patho-biochemistry particularly in relation to different complications like diabetes and ageing discussed. The concept of AGEs receptor - RAGE is mentioned. AGEs contribute to a variety of microvascular and macrovascular complications through the formation of cross-links between molecules in the basement membrane of the extracellular matrix and by engaging the receptor for advanced glycation end products (RAGE). Different methods of detection and quantification along with types of agents used for the treatment of AGEs are reviewed. Generally, ELISA or LC-MS methods are used for analysis of foods and body fluids, however lack of universally established method highlighted. The inhibitory effect of bioactive components on AGEs by trapping variety of chemical moieties discussed. The emerging evidence about the adverse effects of AGEs makes it necessary to investigate the different therapies to inhibit AGEs.

  20. Inhibition of Advanced Glycation End-Product Formation and Antioxidant Activity by Extracts and Polyphenols from Scutellaria alpina L. and S. altissima L.

    OpenAIRE

    Izabela Grzegorczyk-Karolak; Krzysztof Gołąb; Jakub Gburek; Halina Wysokińska; Adam Matkowski

    2016-01-01

    Methanolic extracts from the aerial parts and roots of two Scutellaria species, S. alpina and S. altissima, and five polyphenols from these plants demonstrated a significant ability to inhibit the formation of advanced glycation end-products (AGE) in vitro. S. alpina, which is richer in polyphenolic compounds, had strong antiglycation properties. These extracts demonstrated also high activity in the FRAP (ferric-reducing antioxidant power), antiradical (DPPH) and lipid peroxidation inhibition...

  1. Phenolics from Garcinia mangostana Inhibit Advanced Glycation Endproducts Formation: Effect on Amadori Products, Cross-Linked Structures and Protein Thiols

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    Hossam M. Abdallah

    2016-02-01

    Full Text Available Accumulation of Advanced Glycation Endproducts (AGEs in body tissues plays a major role in the development of diabetic complications. Here, the inhibitory effect of bioactive metabolites isolated from fruit hulls of Garcinia mangostana on AGE formation was investigated through bio-guided approach using aminoguanidine (AG as a positive control. Including G. mangostana total methanol extract (GMT in the reaction mixture of bovine serum albumin (BSA and glucose or ribose inhibited the fluorescent and non-fluorescent AGEs formation in a dose dependent manner. The bioassay guided fractionation of GMT revealed isolation of four bioactive constituents from the bioactive fraction; which were identified as: garcimangosone D (1, aromadendrin-8-C-glucopyranoside (2, epicatechin (3, and 2,3′,4,5′,6-pentahydroxybenzophenone (4. All the tested compounds significantly inhibited fluorescent and non-fluorescent AGEs formation in a dose dependent manner whereas compound 3 (epicatechin was found to be the most potent. In search for the level of action, addition of GMT, and compounds 2–4 inhibited fructosamine (Amadori product and protein aggregation formation in both glucose and ribose. To explore the mechanism of action, it was found that addition of GMT and only compound (3 to reaction mixture increased protein thiol in both glucose and ribose while compounds 1, 2 and 4 only increased thiol in case of ribose. In conclusion, phenolic compounds 1–4 inhibited AGEs formation at the levels of Amadori product and protein aggregation formation through saving protein thiol.

  2. Decreased level of endogenous secretory receptor for advanced glycation end-products in diabetes with concomitant hyperlipidemia.

    Science.gov (United States)

    Turk, Z; Ljubić, S; Boras, J

    2014-01-01

    Endogenous secretory receptor (esRAGE) for advanced glycation end-product (AGE) acts as decoy for AGEs. The AGE-to-esRAGE ratio was hypothesized to be implicated in diabetic vasculopathy. We investigated an association of esRAGE and methylglyoxal-adducts serum level, as well as AGE-to-esRAGE ratio in subpopulation of diabetic patients with or without concomitant hyperlipidemia and macrovascular disease in history. In diabetes with concomitant hyperlipidemia esRAGE was significantly decreased compared to hyperlipidemia with normal glucose metabolism (0.306+/-0.2 vs. 0.367+/-0.1; p=0.019) or diabetes alone (0.306+/-0.2 vs. 0.404+/-0.1; p=0.004). High AGE/esRAGE ratio, found in diabetic patients with hyperlipidemia, pointed to increased production of AGEs and low expression of esRAGE. In multivariable analysis adjusted for several confounding factors, increased AGE/esRAGE ratio was recognized as a high risk for vascular disease outcomes.

  3. Endogenous secretory receptor for advanced glycation end-products inhibits amyloid-β1-42 uptake into mouse brain.

    Science.gov (United States)

    Sugihara, Takahiro; Munesue, Seiichi; Yamamoto, Yasuhiko; Sakurai, Shigeru; Akhter, Nasima; Kitamura, Yoji; Shiba, Kazuhiro; Watanabe, Takuo; Yonekura, Hideto; Hayashi, Yasuhiko; Hamada, Jun-Ichiro; Yamamoto, Hiroshi

    2012-01-01

    The cell-surface receptor for advanced glycation end-products (RAGE) has been implicated in the development of diabetic vascular complications and Alzheimer's disease. RAGE has been considered to be involved in amyloid-β1-42 (Aβ1-42) uptake into brain. In the present study, we demonstrate that endogenous secretory RAGE (esRAGE), a decoy form of RAGE generated by alternative RNA processing, is able to inhibit Aβ1-42 influx into mouse brain. Surface plasmon resonance and competitive binding assays revealed that human Aβ1-42 interacted with human esRAGE within the immunoglobulin V type region. We next examined the uptake and distribution of 125I-labeled human Aβ1-42 in various organs and body fluids of newly created mice overexpressing human esRAGE as well as RAGE-null and wild-type (WT) mice. The transition of the 125I-labeled Aβ1-42 from circulation to brain parenchyma peaked at 30 min after the injection into WT mice, but this was significantly blunted in esRAGE-overexpressing and RAGE-null mice. Significant reduction in 125I-labeled Aβ1-42-derived photo-stimulated luminescence were marked in ventricles, cerebral cortex, hippocampus, especially CA1 and CA3 regions, putamen, and thalamus. The results thus suggest the potential of esRAGE in protection against the development of Alzheimer's disease.

  4. Advanced glycation end-products in the peritoneal fluid and in the peritoneal membrane of continuous ambulant peritoneal dialysis patients.

    Science.gov (United States)

    Mahiout, A; Ehlerding, G; Brunkhorst, R

    1996-01-01

    In patients on continuous ambulant peritoneal dialysis (CAPD) treatment, the peritoneal membrane is continuously exposed to the high glucose concentration contained in the dialysate. This may lead to the local generation of advanced glycation end-products (AGEs). To test this hypothesis we evaluated the plasma and dialysate AGE concentrations in five CAPD patients. The dialysate was measured after a 1 h and after a 12 h dwell time. Additionally, in two patients an immunohistochemical investigation of the peritoneal membrane for AGE was performed. For the determination of AGE an ELISA using a polyclonal antibody against AGE bovine serum albumin was used; the immunohistochemical staining was performed using the streptavidin-biotin complex method. We found only low concentrations of AGE in the dialysate after a 1 h dwell time; after 12 h, however, the dialysate AGE was even greater than the plasma concentration. In both peritoneal specimens we found positive staining for AGE in the interstitium of the mesothelial layer. The dialysate AGE contained a high proportion of high-molecular-weight AGE proteins and low-molecular-weight AGE was found to be in the same concentration range as the total serum AGE. We conclude that there is local generation of AGE in the peritoneal membrane and a 'washing out' of AGE from the peritoneal membrane during longer dwell times. We speculate that the accumulation of AGE might lead to some of the functional and morphological alterations observed after long-term CAPD.

  5. Phytochemicals from Camellia nitidissima Chi inhibited the formation of advanced glycation end-products by scavenging methylglyoxal.

    Science.gov (United States)

    Wang, Weixin; Liu, Haiyan; Wang, Zhennan; Qi, Jing; Yuan, Shengtao; Zhang, Weijie; Chen, Hongjuan; Finley, John W; Gu, Liwei; Jia, Ai-Qun

    2016-08-15

    The objective of this study was to investigate the inhibitory effects of Camellia nitidissima Chi (CNC) on the advanced glycation end-product (AGE) formation. CNC was extracted with ethanol and further separated into dichloromethane, ethyl acetate, n-butanol, and water soluble fractions. Ethyl acetate fraction had the highest total phenolic and quercetin content compared with other fractions. Sixteen phenolic compounds were identified using HPLC Triple TOF MS/MS. Bovine serum albumin (BSA)-glucose assay showed that dichloromethane and ethyl acetate fraction inhibited AGE formation by 88.1% and 87.5% at 2.5mg/mL. BSA-methylglyoxal assay showed that ethyl acetate fraction inhibited 54.1% AGE formation while dichloromethane fraction inhibited 28.1%. Over 96.0% of methylglyoxal was scavenged by different fractions within 12h. Both mono- and di-methylglyoxal quercetin adducts were identified after incubating quercetin with methylglyoxal using HPLC-ESI-MS(n). The results in this study suggest that CNC extracts inhibited AGEs formation in part through scavenging methylglyoxal by phenolic compounds.

  6. Blockade of advanced glycation end-product formation restores ischemia-induced angiogenesis in diabetic mice.

    Science.gov (United States)

    Tamarat, Radia; Silvestre, Jean-Sébastien; Huijberts, Maya; Benessiano, Joelle; Ebrahimian, Teni G; Duriez, Micheline; Wautier, Marie-Paule; Wautier, Jean Luc; Lévy, Bernard I

    2003-07-08

    We hypothesized that formation of advanced glycation end products (AGEs) associated with diabetes reduces matrix degradation by metalloproteinases (MMPs) and contributes to the impairment of ischemia-induced angiogenesis. Mice were treated or not with streptozotocin (40 mg/kg) and streptozotocin plus aminoguanidine (AGEs formation blocker, 50 mg/kg). After 8 weeks of treatment, hindlimb ischemia was induced by right femoral artery ligature. Plasma AGE levels were strongly elevated in diabetic mice when compared with control mice (579 +/- 21 versus 47 +/- 4 pmol/ml, respectively; P < 0.01). Treatment with aminoguanidine reduced AGE plasma levels when compared with untreated diabetic mice (P < 0.001). After 28 days of ischemia, ischemic/nonischemic leg angiographic score, capillary density, and laser Doppler skin-perfusion ratios were 1.4-, 1.5-, and 1.4-fold decreased in diabetic mice in reference to controls (P < 0.01). Treatment with aminoguanidine completely normalized ischemia-induced angiogenesis in diabetic mice. We next analyzed the role of proteolysis in AGE formation-induced hampered neovascularization process. After 3 days of ischemia, MMP-2 activity and MMP-3 and MMP-13 protein levels were increased in untreated and aminoguanidine-treated diabetic mice when compared with controls (P < 0.05). Despite this activation of the MMP pathway, collagenolysis was decreased in untreated diabetic mice. Conversely, treatment of diabetic mice with aminoguanidine restored collagenolysis toward levels found in control mice. In conclusion, blockade of AGE formation by aminoguanidine normalizes impaired ischemia-induced angiogenesis in diabetic mice. This effect is probably mediated by restoration of matrix degradation processes that are disturbed as a result of AGE accumulation.

  7. Dietary advanced glycation end-products aggravate non-alcoholic fatty liver disease

    Science.gov (United States)

    Leung, Christopher; Herath, Chandana B; Jia, Zhiyuan; Andrikopoulos, Sof; Brown, Bronwyn E; Davies, Michael J; Rivera, Leni R; Furness, John B; Forbes, Josephine M; Angus, Peter W

    2016-01-01

    AIM To determine if manipulation of dietary advanced glycation end product (AGE), intake affects non-alcoholic fatty liver disease (NAFLD) progression and whether these effects are mediated via RAGE. METHODS Male C57Bl6 mice were fed a high fat, high fructose, high cholesterol (HFHC) diet for 33 wk and compared with animals on normal chow. A third group were given a HFHC diet that was high in AGEs. Another group was given a HFHC diet that was marinated in vinegar to prevent the formation of AGEs. In a second experiment, RAGE KO animals were fed a HFHC diet or a high AGE HFHC diet and compared with wildtype controls. Hepatic biochemistry, histology, picrosirius red morphometry and hepatic mRNA were determined. RESULTS Long-term consumption of the HFHC diet generated significant steatohepatitis and fibrosis after 33 wk. In this model, hepatic 4-hydroxynonenal content (a marker of chronic oxidative stress), hepatocyte ballooning, picrosirius red staining, α-smooth muscle actin and collagen type 1A gene expression were all significantly increased. Increasing the AGE content of the HFHC diet by baking further increased these markers of liver damage, but this was abrogated by pre-marination in acetic acid. In response to the HFHC diet, RAGE-/- animals developed NASH of similar severity to RAGE+/+ animals but were protected from the additional harmful effects of the high AGE containing diet. Studies in isolated Kupffer cells showed that AGEs increase cell proliferation and oxidative stress, providing a likely mechanism through which these compounds contribute to liver injury. CONCLUSION In the HFHC model of NAFLD, manipulation of dietary AGEs modulates liver injury, inflammation, and liver fibrosis via a RAGE dependent pathway. This suggests that pharmacological and dietary strategies targeting the AGE/RAGE pathway could slow the progression of NAFLD. PMID:27672297

  8. Anti-Advanced Glycation End-product and Free Radical Scavenging Activity of Plants from the Yucatecan Flora

    Science.gov (United States)

    Dzib-Guerra, Wendy del C.; Escalante-Erosa, Fabiola; García-Sosa, Karlina; Derbré, Séverine; Blanchard, Patricia; Richomme, Pascal; Peña-Rodríguez, Luis M.

    2016-01-01

    Background: Formation and accumulation of advanced glycation end-products (AGE) is recognized as a major pathogenic process in diabetic complications, atherosclerosis and cardiovascular diseases. In addition, reactive oxygen species and free radicals have also been reported to participate in AGE formation and in cell damage. Natural products with antioxidant and antiAGE activity have great therapeutic potential in the treatment of diabetes, hypertension and related complications. Objective: to test ethanolic extracts and aqueous-traditional preparations of plants used to treat diabetes, hypertension and obesity in Yucatecan traditional medicine for their anti-AGE and free radical scavenging activities. Materials and Methods: ethanolic extracts of leaves, stems and roots of nine medicinal plants, together with their traditional preparations, were prepared and tested for their anti-AGE and antioxidant activities using the inhibition of advanced glycation end products and DPPH radical scavenging assays, respectively. Results: the root extract of C. fistula (IC50= 0.1 mg/mL) and the leaf extract of P. auritum (IC50= 0.35 mg/mL) presented significant activity against vesperlysine and pentosidine-like AGE. Although none of the aqueous traditional preparations showed significant activity in the anti-AGE assay, both the traditional preparations and the ethanolic extracts of E. tinifolia, M. zapota, O. campechianum and P. auritum showed significant activity in the DPPH reduction assay. Conclusions: the results suggest that the metabolites responsible for the detected radical-scavenging activity are different to those involved in inhibiting AGE formation; however, the extracts with antioxidant activity may contain other metabolites which are able to prevent AGE formation through a different mechanism. SUMMARY Ethanolic extracts from nine plants used to treat diabetes, hypertension and obesity in Yucatecan traditional medicine were tested for their anti-AGE and free radical

  9. The role of the receptor for advanced glycation end-products in a murine model of silicosis.

    Directory of Open Access Journals (Sweden)

    Lasse Ramsgaard

    Full Text Available BACKGROUND: The role of the receptor for advanced glycation end-products (RAGE has been shown to differ in two different mouse models of asbestos and bleomycin induced pulmonary fibrosis. RAGE knockout (KO mice get worse fibrosis when challenged with asbestos, whereas in the bleomycin model they are largely protected against fibrosis. In the current study the role of RAGE in a mouse model of silica induced pulmonary fibrosis was investigated. METHODOLOGY/PRINCIPAL FINDINGS: Wild type (WT and RAGE KO mice received a single intratracheal (i.t. instillation of silica in saline or saline alone as vehicle control. Fourteen days after treatment mice were subjected to a lung mechanistic study and the lungs were lavaged and inflammatory cells, protein and TGF-beta levels in lavage fluid determined. Lungs were subsequently either fixed for histology or excised for biochemical assessment of fibrosis and determination of RAGE protein- and mRNA levels. There was no difference in the inflammatory response or degree of fibrosis (hydroxyproline levels in the lungs between WT and RAGE KO mice after silica injury. However, histologically the fibrotic lesions in the RAGE KO mice had a more diffuse alveolar septal fibrosis compared to the nodular fibrosis in WT mice. Furthermore, RAGE KO mice had a significantly higher histologic score, a measure of affected areas of the lung, compared to WT silica treated mice. A lung mechanistic study revealed a significant decrease in lung function after silica compared to control, but no difference between WT and RAGE KO. While a dose response study showed similar degrees of fibrosis after silica treatment in the two strains, the RAGE KO mice had some differences in the inflammatory response compared to WT mice. CONCLUSIONS/SIGNIFICANCE: Aside from the difference in the fibrotic pattern, these studies showed no indicators of RAGE having an effect on the severity of pulmonary fibrosis following silica injury.

  10. Skin Autofluorescence Relates to Soluble Receptor for Advanced Glycation End-Products and Albuminuria in Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    J. Škrha

    2013-01-01

    Full Text Available The aim of this study was to compare skin autofluorescence caused by advanced glycation end-products (AGEs with biochemical markers of endothelial dysfunction and soluble receptor for AGEs (sRAGE in patients with diabetes. Skin autofluorescence (AF assessed by AGE-Reader was evaluated with sRAGE and other biochemical parameters in 88 patients with diabetes (47 Type 1/T1DM/ and 41 Type 2/T2DM/ and 20 controls. Skin AF was significantly higher in T1DM and T2DM in comparison to controls (2.39 ± 0.54, 2.63 ± 0.73 versus 1.96 ± 0.33 AU; P<0.0001. Positive correlation of AF with sRAGE was detected in T1DM and T2DM (r=0.37, P<0.02 and r=0.60, P<0.0001, but not in controls. Significantly higher AF values were found in patients with positive albuminuria as compared to those with normal albuminuria. Similarly, higher AF was detected in patients with endothelial dysfunction expressed by vWF, ICAM-1, and VCAM-1. Multiple regression analysis revealed independent association of skin AF with age, sRAGE, and albumin-creatinine ratio in patients with diabetes (R2=0.38. Our study confirms that AF is elevated in patients with diabetes, especially with positive albuminuria and endothelial dysfunction. The strong and independent relationship between AF and sRAGE supports the idea that AF may reflect AGEs/RAGE interactions. The exact mechanism remains to be established.

  11. Skin autofluorescence relates to soluble receptor for advanced glycation end-products and albuminuria in diabetes mellitus.

    Science.gov (United States)

    Skrha, J; Soupal, J; Loni Ekali, G; Prázný, M; Kalousová, M; Kvasnička, J; Landová, L; Zima, T; Skrha, J

    2013-01-01

    The aim of this study was to compare skin autofluorescence caused by advanced glycation end-products (AGEs) with biochemical markers of endothelial dysfunction and soluble receptor for AGEs (sRAGE) in patients with diabetes. Skin autofluorescence (AF) assessed by AGE-Reader was evaluated with sRAGE and other biochemical parameters in 88 patients with diabetes (47 Type 1/T1DM/ and 41 Type 2/T2DM/) and 20 controls. Skin AF was significantly higher in T1DM and T2DM in comparison to controls (2.39 ± 0.54, 2.63 ± 0.73 versus 1.96 ± 0.33 AU; P < 0.0001). Positive correlation of AF with sRAGE was detected in T1DM and T2DM (r = 0.37, P < 0.02 and r = 0.60, P < 0.0001), but not in controls. Significantly higher AF values were found in patients with positive albuminuria as compared to those with normal albuminuria. Similarly, higher AF was detected in patients with endothelial dysfunction expressed by vWF, ICAM-1, and VCAM-1. Multiple regression analysis revealed independent association of skin AF with age, sRAGE, and albumin-creatinine ratio in patients with diabetes (R (2) = 0.38). Our study confirms that AF is elevated in patients with diabetes, especially with positive albuminuria and endothelial dysfunction. The strong and independent relationship between AF and sRAGE supports the idea that AF may reflect AGEs/RAGE interactions. The exact mechanism remains to be established.

  12. Advanced Glycation End-Products Induce Apoptosis of Vascular Smooth Muscle Cells: A Mechanism for Vascular Calcification

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    Sayo Koike

    2016-09-01

    Full Text Available Vascular calcification, especially medial artery calcification, is associated with cardiovascular death in patients with diabetes mellitus and chronic kidney disease (CKD. To determine the underlying mechanism of vascular calcification, we have demonstrated in our previous report that advanced glycation end-products (AGEs stimulated calcium deposition in vascular smooth muscle cells (VSMCs through excessive oxidative stress and phenotypic transition into osteoblastic cells. Since AGEs can induce apoptosis, in this study we investigated its role on VSMC apoptosis, focusing mainly on the underlying mechanisms. A rat VSMC line (A7r5 was cultured, and treated with glycolaldehyde-derived AGE-bovine serum albumin (AGE3-BSA. Apoptotic cells were identified by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL staining. To quantify apoptosis, an enzyme-linked immunosorbent assay (ELISA for histone-complexed DNA fragments was employed. Real-time PCR was performed to determine the mRNA levels. Treatment of A7r5 cells with AGE3-BSA from 100 µg/mL concentration markedly increased apoptosis, which was suppressed by Nox inhibitors. AGE3-BSA significantly increased the mRNA expression of NAD(PH oxidase components including Nox4 and p22phox, and these findings were confirmed by protein levels using immunofluorescence. Dihydroethidisum assay showed that compared with cBSA, AGE3-BSA increased reactive oxygen species level in A7r5 cells. Furthermore, AGE3-induced apoptosis was significantly inhibited by siRNA-mediated knockdown of Nox4 or p22phox. Double knockdown of Nox4 and p22phox showed a similar inhibitory effect on apoptosis as single gene silencing. Thus, our results demonstrated that NAD(PH oxidase-derived oxidative stress are involved in AGEs-induced apoptosis of VSMCs. These findings might be important to understand the pathogenesis of vascular calcification in diabetes and CKD.

  13. Advanced glycation end-products reduce collagen molecular sliding to affect collagen fibril damage mechanisms but not stiffness.

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    Gion Fessel

    Full Text Available Advanced glycation end-products (AGE contribute to age-related connective tissue damage and functional deficit. The documented association between AGE formation on collagens and the correlated progressive stiffening of tissues has widely been presumed causative, despite the lack of mechanistic understanding. The present study investigates precisely how AGEs affect mechanical function of the collagen fibril--the supramolecular functional load-bearing unit within most tissues. We employed synchrotron small-angle X-ray scattering (SAXS and carefully controlled mechanical testing after introducing AGEs in explants of rat-tail tendon using the metabolite methylglyoxal (MGO. Mass spectrometry and collagen fluorescence verified substantial formation of AGEs by the treatment. Associated mechanical changes of the tissue (increased stiffness and failure strength, decreased stress relaxation were consistent with reports from the literature. SAXS analysis revealed clear changes in molecular deformation within MGO treated fibrils. Underlying the associated increase in tissue strength, we infer from the data that MGO modified collagen fibrils supported higher loads to failure by maintaining an intact quarter-staggered conformation to nearly twice the level of fibril strain in controls. This apparent increase in fibril failure resistance was characterized by reduced side-by-side sliding of collagen molecules within fibrils, reflecting lateral molecular interconnectivity by AGEs. Surprisingly, no change in maximum fibril modulus (2.5 GPa accompanied the changes in fibril failure behavior, strongly contradicting the widespread assumption that tissue stiffening in ageing and diabetes is directly related to AGE increased fibril stiffness. We conclude that AGEs can alter physiologically relevant failure behavior of collagen fibrils, but that tissue level changes in stiffness likely occur at higher levels of tissue architecture.

  14. Relationship between advanced glycation end-products with the severity of chronic heart failure in 85 patients

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    Amir Farhang Zand Parsa

    2013-12-01

    Full Text Available Background: Advanced glycation end-products (AGEs came up with the recent researches regarding new biomarkers for the diagnosis of heart failure. AGEs are the end products of non-enzymatic glycation and oxidation of proteins, lipids and nucleotides during Maillard biochemical reaction. Although it has been known that AGEs have a role in the pathogenesis of chronic heart failure (CHF, information regarding its role and its pathogenetic mechanism is very limited. The aim of this study was to find any relationship between AGEs with the etiology and severity of chronic heart failure.Methods: This study is a prospective cross sectional study that enrolled 85 patients with chronic heart failure. Measurement of left ventricle ejection fraction (LVEF was done by echocardiography. Blood samples were collected for measuring AGEs just before or after echocardiography assessment (in the same session. Measurement of AGEs was done by the enzyme-linked immunosorbent assay (ELISA method. The relationship between AGEs with the severity of CHF and as well as the etiology of CHF were evaluated via SPSS-15.Results: Of 85 patients 48 (56.5% patients were male and 37 (43.5% were female; Mean±SD of their ages was 55.8±13.4 years old (ranges from 27 to 84 years. Correlation coefficient between LVEF and AGEs was 0.269 (P=0.013. Mean of AGEs in patients with and without ischemic etiology of their heart failure were 16.8±9.8µg/ml and 11.6±7.3 µg/ml, respectively. Although trend was in favor of ischemic heart failure, the difference between two groups was not statistically significant (P= 0.141.Conclusion: According to this study the rate of AGES could be helpful in the diagnosis and assessment of severity of CHF. Based on our findings, higher blood levels of AGEs in the ischemic CHF cases, also it could be concluded that in the future this marker may be used for etiologic differentiation of heart failure syndrome.

  15. Expression of receptor for advanced glycation endproducts and nuclear factor κB in brain hippocampus of rat with chronic fluorosis

    Institute of Scientific and Technical Information of China (English)

    张凯琳

    2014-01-01

    Objective To investigate the expressions of receptor for advanced glycation endproducts(RAGE)and nuclear factorκB(NF-κB)in brain hippocampus of rat with chronic fluorosis,and to reveal the mechanism of brain damage resulted from chronic fluorosis.Methods Sixty clean grade SD rats were randomly divided to three groups(20 rats in each group,10 female and 10 male)fed with different contents of fluoride,control group with normal tap-water(<0.5 mg/L fluoride),

  16. Characterizing harmful advanced glycation end-products (AGEs) and ribosylated aggregates of yellow mustard seed phytocystatin: Effects of different monosaccharides

    Science.gov (United States)

    Ahmed, Azaj; Shamsi, Anas; Bano, Bilqees

    2017-01-01

    Advanced glycation end products (AGEs) are at the core of variety of diseases ranging from diabetes to renal failure and hence gaining wide consideration. This study was aimed at characterizing the AGEs of phytocystatin isolated from mustard seeds (YMP) when incubated with different monosaccharides (glucose, ribose and mannose) using fluorescence, ultraviolet, circular dichroism (CD) spectroscopy and microscopy. Ribose was found to be the most potent glycating agent as evident by AGEs specific fluorescence and absorbance. YMP exists as a molten globule like structure on day 24 as depicted by high ANS fluorescence and altered intrinsic fluorescence. Glycated YMP as AGEs and ribose induced aggregates were observed at day 28 and 32 respectively. In our study we have also examined the anti-aggregative potential of polyphenol, resveratrol. Our results suggested the anti-aggregative behavior of resveratrol as it prevented the in vitro aggregation of YMP, although further studies are required to decode the mechanism by which resveratrol prevents the aggregation.

  17. Advanced glycation end-products induce heparanase expression in endothelial cells by the receptor for advanced glycation end products and through activation of the FOXO4 transcription factor.

    Science.gov (United States)

    An, Xiao-Fei; Zhou, Lei; Jiang, Peng-Jun; Yan, Ming; Huang, Yu-Jun; Zhang, Su-Na; Niu, Yun-Fei; Ten, Shi-Chao; Yu, Jiang-Yi

    2011-08-01

    As an endo-β (1-4)-D: -glucuronidase, heparanase can specifically cleave carbohydrate chains of heparan sulfate (HS) and has been implicated in development of endothelial cells dsyfunction. The advanced glycation end products (AGEs) play a pivotal role in the pathology of diabetic complications. In the present study, we investigated the effect of AGE-bovine serum albumin (AGE-BSA) on heparanase expression in human microvascular endothelial cells (HMVECs) and the underlying molecular mechanisms. The results indicated that in vitro direct exposure of HMVECs to AGE-BSA (300, 1000, and 3000 μg/ml) could increase heparanase mRNA and protein expression in a dose and time-dependent manner. The effect of 1000 μg/ml AGE-BSA could be abolished by neutralization with antibody of the receptor for advanced glycation end products (RAGE). Moreover, pretreatment with inhibitors of nuclear factor-κB (NF-κB) or PI3-kinase did not affect heparanase expression induced by AGE-BSA. Nevertheless, small interference RNA (siRNA) for transcriptional factor FOXO4 could reduce the increase of heparanase expression in HMVECs induced by 1000 μg/ml AGE-BSA. These results suggest that AGEs could induce heparanase expression in HMVECs by RAGE and predominantly through activation of the FOXO4 transcription factor.

  18. Association of the receptor for advanced glycation end-products (RAGE gene polymorphisms in Malaysian patients with chronic kidney disease

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    Foo Nian Wong

    2016-04-01

    Full Text Available Background: Chronic kidney disease (CKD is a condition associated with progressive loss of kidney function and kidney damage. The two common causes of CKD are diabetes mellitus and hypertension. Other causes of CKD also include polycystic kidney disease, obstructive uropathy and primary glomerulonephritis. The receptor for advanced glycation end-products (RAGE is a multi-ligand cell surface receptor of the immunoglobulin superfamily and it has been associated with kidney disease in both non-diabetic and diabetic patients. Presently, data on the association between RAGE polymorphisms and CKD in the Malaysian population is limited, while numerous studies have reported associations of RAGE polymorphisms with diabetic complications in other populations. The present study aims to explore the possibility of using RAGE polymorphisms as candidate markers of CKD in Malaysian population by using association analysis. Methods: A total of 102 non-diabetic CKD patients, 204 diabetic CKD patients and 345 healthy controls were enrolled in the study. DNA isolated from blood samples were subjected to genotyping of RAGE G82S, −374T/A, −429T/C, 1704G/T and 2184A/G polymorphisms using real-time polymerase chain reaction (PCR. The 63-bp deletion, a polymorphism in the RAGE gene promoter, was genotyped using conventional PCR method and visualized using agarose gel electrophoresis. The collective frequencies of genotypes with at least one copy of the minor alleles of the four polymorphisms were compared between the non-diabetic CKD patients, diabetic CKD patients and healthy controls. Results: After adjustment of age, gender and ethnic groups in binary logistic regression analysis, the G82S CT + TT genotypes were associated with non-diabetic CKD patients when compared with diabetic CKD patients (p = 0.015, OR = 1.896, 95% CI = 1.132–3.176. After further adjustment of CKD comorbidities, the G82S CT + TT genotypes were still associated with non-diabetic CKD

  19. The association between the -374T/A polymorphism of the receptor for advanced glycation endproducts gene and blood pressure and arterial stiffness is modified by glucose metabolism status: the Hoorn and CoDAM studies

    NARCIS (Netherlands)

    Engelen, L.; Ferreira, I.; Gaens, K.H.; Henry, R.; Dekker, J.M.; Nijpels, G.; Heine, R.J.; Hart, t L.M.; Greevenboek, van M.M.; Kallen, C.J.; Blaak, E.E.; Feskens, E.J.M.; Cate, ten H.; Stehouwer, C.D.; Schalkwijk, C.G.

    2010-01-01

    Objectives: Receptor for advanced glycation endproducts (RAGE)–ligand interaction may lead to vascular complications. Genetic variation in RAGE has been shown to alter expression, activity of RAGE or both. We, therefore, investigated whether RAGE single-nucleotide polymorphisms (SNPs) and haplotypes

  20. Vitamin A (retinol) up-regulates the receptor for advanced glycation endproducts (RAGE) through p38 and Akt oxidant-dependent activation.

    Science.gov (United States)

    Gelain, Daniel Pens; de Bittencourt Pasquali, Matheus Augusto; Caregnato, Fernanda Freitas; Moreira, José Claudio Fonseca

    2011-10-28

    Retinol (vitamin A) is believed to exert preventive/protective effects against malignant, neurodegenerative and cardiovascular diseases by acting as an antioxidant. However, later clinical and experimental data show a pro-oxidant action of retinol and other retinoids at specific conditions. The receptor for advanced glycation endproducts (RAGE) is a pattern recognition receptor, being activated by different ligands such as S100 proteins, HMGB1 (amphoterin), β-amyloid peptide and advanced glycation endproducts (AGE). RAGE activation influences a wide range of pathological conditions such as diabetes, pro-inflammatory states and neurodegenerative processes. Here, we investigated the involvement of different mitogen-activated protein kinases (MAPK: ERK1/2, p38 and JNK), PKC, PKA and Akt in the up-regulation of RAGE by retinol. As previously reported, we observed that the increase in RAGE immunocontent by retinol is reversed by antioxidant co-treatment, indicating the involvement of oxidative stress in this process. Furthermore, the p38 inhibitor SB203580 and the Akt inhibitor LY294002 also decreased the effect of retinol on RAGE levels, suggesting the involvement of these protein kinases in such effect. Both p38 and Akt phosphorylation were increased by treatment with pro-oxidant concentrations of retinol, and the antioxidant co-treatment blocked this effect, indicating that activation of p38 and Akt during retinol treatment is dependent on reactive species production. The 2',7'-dichlorohydrofluorescein diacetate (DCFH) assay also indicated that retinol treatment enhances cellular reactive species production. Altogether, these data indicate that RAGE up-regulation by retinol is mediated by the free radical-dependent activation of p38 and Akt.

  1. Soluble Forms and Ligands of the Receptor for Advanced Glycation End-Products in Patients with Acute Respiratory Distress Syndrome: An Observational Prospective Study.

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    Matthieu Jabaudon

    Full Text Available The main soluble form of the receptor for advanced glycation end-products (sRAGE is elevated during acute respiratory distress syndrome (ARDS. However other RAGE isoforms and multiple ligands have been poorly reported in the clinical setting, and their respective contribution to RAGE activation during ARDS remains unclear. Our goal was therefore to describe main RAGE isoforms and ligands levels during ARDS.30 ARDS patients and 30 mechanically ventilated controls were prospectively included in this monocenter observational study. Arterial, superior vena cava and alveolar fluid levels of sRAGE, endogenous-secretory RAGE (esRAGE, high mobility group box-1 protein (HMGB1, S100A12 and advanced glycation end-products (AGEs were measured in duplicate ELISA on day 0, day 3 and day 6. In patients with ARDS, baseline lung morphology was assessed with computed tomography.ARDS patients had higher arterial, central venous and alveolar levels of sRAGE, HMGB1 and S100A12, but lower levels of esRAGE and AGEs, than controls. Baseline arterial sRAGE, HMGB1 and S100A12 were correlated with nonfocal ARDS (AUC 0.79, 0.65 and 0.63, respectively. Baseline arterial sRAGE, esRAGE, S100A12 and AGEs were associated with severity as assessed by PaO2/FiO2.This is the first kinetics study of levels of RAGE main isoforms and ligands during ARDS. Elevated sRAGE, HMGB1 and S100A12, with decreased esRAGE and AGEs, were found to distinguish patients with ARDS from those without. Our findings should prompt future studies aimed at elucidating RAGE/HMGB1/S100A12 axis involvement in ARDS.clinicaltrials.gov Identifier: NCT01270295.

  2. Phlorotannins from brown algae (Fucus vesiculosus) inhibited the formation of advanced glycation endproducts by scavenging reactive carbonyls.

    Science.gov (United States)

    Liu, Haiyan; Gu, Liwei

    2012-02-08

    Accumulation of advanced glycation end products (AGEs) in vivo is associated with aging, diabetes, Alzheimer's disease, renal failure, etc. The objective of this study was to investigate the inhibitory effects of brown algae Fucus vesiculosus phlorotannins on the formation of AGEs. F. vesiculosus phlorotannins were extracted using 70% acetone. The resultant extract was fractionated into dichloromethane, ethyl acetate, butanol, and water fractions. The ethyl acetate fraction was further fractionated into four subfractions (Ethyl-F1 to -F4) using a Sephadex LH-20 column. F. vesiculosus acetone extract or fractions significantly inhibited the formation of AGEs mediated by glucose and methylglyoxal in a concentration-dependent manner. The concentrations of F. vesiculosus extracts required to inhibit 50% of albumin glycation (EC(50)) in the bovine serum albumin (BSA)-methylglyoxal assay were lower than those of aminoguanidine (a drug candidate for diabetic complication), except for F. vesiculosus acetone extract and dichloromethane fraction. In the BSA-glucose assay, F. vesiculosus extracts inhibited BSA glycation more than or as effectively as aminoguanidine, except for Ethyl-F3 and -F4. The ethyl acetate fraction and its four subfractions scavenged more than 50% of methylglyoxal in two hours. The hypothesis whether F. vesiculosus phlorotannins scavenged reactive carbonyls by forming adducts was tested. Phloroglucinol, the constituent unit of phlorotannins, reacted with glyoxal and methylglyoxal. Five phloroglucinol-carbonyl adducts were detected and tentatively identified using HPLC-ESI-MS(n).

  3. p-Dimethylaminobenzaldehyde-reactive substances in tail tendon collagen of streptozotocin-diabetic rats: temporal relation to biomechanical properties and advanced glycation endproduct (AGE)-related fluorescence.

    Science.gov (United States)

    Stefek, M; Gajdosik, A; Gajdosikova, A; Krizanova, L

    2000-11-15

    In the present work, pepsin digests of tail tendons from streptozotocin-diabetic rats were found to contain material that reacted rapidly at room temperature with p-dimethylaminobenzaldehyde (Ehrlich's reagent) to give an adduct with an absorbance spectrum characteristic of the Ehrlich chromogen of pyrrolic nature determined in ageing collagens. A significant correlation of the Ehrlich adduct with tendon mechanical strength and collagen fluorescence characteristic of advanced glycation endproducts was observed. Collagen content of the Ehrlich-positive material was found to be significantly elevated in tendons of diabetic rats compared with age-matched healthy controls. The results indicate that the p-dimethylaminobenzaldehyde-reactive pyrrole moieties may contribute to the increased cross-linking of diabetic matrix collagen. Profound inhibitory effect of aminoguanidine was observed, underlining the role of non-enzymatic mechanisms of advanced glycation in pyrrolisation and cross-linking of collagen exposed to hyperglycaemia. It is hypothesised that quantification of the p-dimethylaminobenzaldehyde-reactive material in matrix collagen may provide a tissue measure of integrated hyperglycaemia over prolonged periods of time. Further research is to assess the significance of p-dimethylaminobenzaldehyde-reactive substances in diabetic collagen tissues and to reveal their relationship to enzyme-mediated physiological pyrrolisation of ageing collagens.

  4. Inhibition of Advanced Glycation End-Product Formation and Antioxidant Activity by Extracts and Polyphenols from Scutellaria alpina L. and S. altissima L.

    Science.gov (United States)

    Grzegorczyk-Karolak, Izabela; Gołąb, Krzysztof; Gburek, Jakub; Wysokińska, Halina; Matkowski, Adam

    2016-06-14

    Methanolic extracts from the aerial parts and roots of two Scutellaria species, S. alpina and S. altissima, and five polyphenols from these plants demonstrated a significant ability to inhibit the formation of advanced glycation end-products (AGE) in vitro. S. alpina, which is richer in polyphenolic compounds, had strong antiglycation properties. These extracts demonstrated also high activity in the FRAP (ferric-reducing antioxidant power), antiradical (DPPH) and lipid peroxidation inhibition assays. Among the pure compounds, baicalin was the strongest glycation inhibitor (90.4% inhibition at 100 μg/mL), followed by luteolin (85.4%). Two other flavone glycosides had about half of this activity. Verbascoside was similar to the reference drug aminoguanidine (71.2% and 75.9%, respectively). The strong correlation observed between AGE inhibition and total flavonoid content indicated that flavonoids contribute significantly to antiglycation properties. A positive correlation was also observed between antiglycative and antioxidant activities. The studied skullcap species can be considered as a potential source of therapeutic agents for hyperglycemia-related disorders.

  5. Inhibition of Advanced Glycation End-Product Formation and Antioxidant Activity by Extracts and Polyphenols from Scutellaria alpina L. and S. altissima L.

    Directory of Open Access Journals (Sweden)

    Izabela Grzegorczyk-Karolak

    2016-06-01

    Full Text Available Methanolic extracts from the aerial parts and roots of two Scutellaria species, S. alpina and S. altissima, and five polyphenols from these plants demonstrated a significant ability to inhibit the formation of advanced glycation end-products (AGE in vitro. S. alpina, which is richer in polyphenolic compounds, had strong antiglycation properties. These extracts demonstrated also high activity in the FRAP (ferric-reducing antioxidant power, antiradical (DPPH and lipid peroxidation inhibition assays. Among the pure compounds, baicalin was the strongest glycation inhibitor (90.4% inhibition at 100 μg/mL, followed by luteolin (85.4%. Two other flavone glycosides had about half of this activity. Verbascoside was similar to the reference drug aminoguanidine (71.2% and 75.9%, respectively. The strong correlation observed between AGE inhibition and total flavonoid content indicated that flavonoids contribute significantly to antiglycation properties. A positive correlation was also observed between antiglycative and antioxidant activities. The studied skullcap species can be considered as a potential source of therapeutic agents for hyperglycemia-related disorders.

  6. Advanced glycation end-product expression is upregulated in the gastrointestinal tract of type 2 diabetic rats

    DEFF Research Database (Denmark)

    Chen, Peng-Min; Gregersen, Hans; Zhao, Jingbo

    2015-01-01

    AIM: To investigate changes in advanced glycation end products (AGEs) and their receptor (RAGE) expression in the gastrointestinal (GI) tract in type 2 diabetic rats. METHODS: Eight inherited type 2 diabetic rats Goto-Kakizak (GK) and ten age-matched normal rats were used in the study. From 18 wk...... and five micron sections were cut. The layer thickness was measured in Hematoxylin and Eosin-stained slides. AGE [N epsilon-(carboxymethyl) lysine and N epsilon-(carboxyethyl)lysine] and RAGE were detected by immunohistochemistry staining and image analysis was done using Sigmascan Pro 4.0 image analysis......-regulated in the GI tract of GK diabetic rats and may contribute to GI dysfunction in type 2 diabetic patients....

  7. Pomegranate (Punicagranatum) juice decreases lipid peroxidation, but has no effect on plasma advanced glycated end-products in adults with type 2 diabetes: a randomized double-blind clinical trial

    OpenAIRE

    Nasrollahzadeh, Javad; Sohrab, Golbon; Angoorani, Pooneh; Tohidi, Maryam; Tabibi, Hadi; Kimiagar, Masoud

    2015-01-01

    Introduction: Diabetes mellitus characterized by hyperglycemia could increase oxidative stress and formation of advanced glycated end-products (AGEs), which contribute to diabetic complications. The purpose of this study was to assess the effect of pomegranate juice (PJ) containing natural antioxidant on lipid peroxidation and plasma AGEs in patients with type 2 diabetes (T2D).Materials and methods: In a randomized, double-blind, placebo-controlled trial, 44 patients (age range 56±6.8 years),...

  8. Soluble receptor for advanced glycation end-product (sRAGE)/pentosidine ratio: a potential risk factor determinant for type 2 diabetic retinopathy.

    Science.gov (United States)

    Ng, Zhi Xiang; Chua, Kek Heng; Iqbal, Tajunisah; Kuppusamy, Umah Rani

    2013-04-03

    This study aims to investigate potential diabetic retinopathy (DR) risk factors by evaluating the circulating levels of pentosidine, soluble receptor for advanced glycation end-product (sRAGE), advanced oxidation protein product (AOPP) as well as glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in DR patients. A total of 235 healthy controls, 171 type 2 diabetic without retinopathy (DNR) and 200 diabetic retinopathy (DR) patients were recruited. Plasma was extracted for the estimation of pentosidine, sRAGE, AOPP levels and GPx activity whereas peripheral blood mononuclear cells were disrupted for SOD activity measurement. DNR and DR patients showed significantly higher levels of plasma pentosidine, sRAGE and AOPP but lower GPx and SOD activities when compared to healthy controls. The sRAGE/pentosidine ratio in DR patients was significantly lower than the ratio detected in DNR patients. Proliferative DR patients had significantly higher levels of plasma pentosidine, sRAGE, AOPP and sRAGE/pentosidine ratio than non-proliferative DR patients. High HbA1c level, long duration of diabetes and low sRAGE/pentosidine ratio were determined as the risk factors for DR. This study suggests that sRAGE/pentosidine ratio could serve as a risk factor determinant for type 2 DR as it has a positive correlation with the severity of DR.

  9. Curcumin eliminates the effect of advanced glycation end-products (AGEs) on the divergent regulation of gene expression of receptors of AGEs by interrupting leptin signaling.

    Science.gov (United States)

    Tang, Youcai; Chen, Anping

    2014-05-01

    Non-alcoholic steatohepatitis (NASH) is a major risk factor for hepatic fibrogenesis. NASH is often found in diabetic patients with hyperglycemia. Hyperglycemia induces non-enzymatic glycation of proteins, yielding advanced glycation end-products (AGEs). Effects of AGEs are mainly mediated by two categories of cytoplasmic membrane receptors. Receptor for AGEs (RAGE) is associated with increased oxidative stress and inflammation, whereas AGE receptor-1 (AGE-R1) is involved in detoxification and clearance of AGEs. Activation of hepatic stellate cells (HSC) is crucial to the development of hepatic fibrosis. We recently reported that AGEs stimulated HSC activation likely by inhibiting gene expression of AGE-R1 and inducing gene expression of RAGE in HSC, which were eliminated by the antioxidant curcumin. This study is to test our hypothesis that curcumin eliminates the effects of AGEs on the divergent regulation of the two receptors of AGEs in HSC by interrupting the AGE-caused activation of leptin signaling, leading to the inhibition of HSC activation. We observed herein that AGEs activated leptin signaling by inducing gene expression of leptin and its receptor in HSC. Like AGEs, leptin differentially regulated gene expression of RAGE and AGE-R1. Curcumin eliminated the effects of AGEs in HSC by interrupting leptin signaling and activating transcription factor NF-E2 p45-related factor 2 (Nrf2), leading to the elevation of cellular glutathione and the attenuation of oxidative stress. In conclusions, curcumin eliminated the effects of AGEs on the divergent regulation of gene expression of RAGE and AGE-R1 in HSC by interrupting the AGE-caused activation of leptin signaling, leading to the inhibition of HSC activation.

  10. Effect of Amaranthus on Advanced Glycation End-Products Induced Cytotoxicity and Proinflammatory Cytokine Gene Expression in SH-SY5Y Cells

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    Warisa Amornrit

    2015-09-01

    Full Text Available Amaranthus plants, or spinach, are used extensively as a vegetable and are known to possess medicinal properties. Neuroinflammation and oxidative stress play a major role in the pathogenesis of many neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease. Advanced glycation end-products (AGEs cause cell toxicity in the human neuronal cell line, SH-SY5Y, through an increase in oxidative stress, as shown by reducing cell viability and increasing cell toxicity in a dose-dependent manner. We found that preincubation of SH-SY5Y cells with either petroleum ether, dichloromethane or methanol extracts of A. lividus and A. tricolor dose-dependently attenuated the neuron toxicity caused by AGEs treatment. Moreover, the results showed that A. lividus and A. tricolor extracts significantly downregulated the gene expression of the pro-inflammatory cytokines, TNF-α, IL-1 and IL-6 genes in AGEs-induced cells. We concluded that A. lividus and A. tricolor extracts not only have a neuroprotective effect against AGEs toxicity, but also have anti-inflammatory activity by reducing pro-inflammatory cytokine gene expression. This suggests that Amaranthus may be useful for treating chronic inflammation associated with neurodegenerative disorders.

  11. Regulation of alternative splicing of the receptor for advanced glycation endproducts (RAGE) through G-rich cis-elements and heterogenous nuclear ribonucleoprotein H.

    Science.gov (United States)

    Ohe, Kazuyo; Watanabe, Takuo; Harada, Shin-ichi; Munesue, Seiichi; Yamamoto, Yasuhiko; Yonekura, Hideto; Yamamoto, Hiroshi

    2010-05-01

    Receptor for advanced glycation endproducts (RAGE) is a cell-surface receptor. The binding of ligands to membrane-bound RAGE (mRAGE) evokes cellular responses involved in various pathological processes. Previously, we identified a novel soluble form, endogenous secretory RAGE (esRAGE) generated by alternative 5' splice site selection in intron 9 that leads to extension of exon 9 (exon 9B). Because esRAGE works as an antagonistic decoy receptor, the elucidation of regulatory mechanism of the alternative splicing is important to understand RAGE-related pathological processes. Here, we identified G-rich cis-elements within exon 9B for regulation of the alternative splicing using a RAGE minigene. Mutagenesis of the G-rich cis-elements caused a drastic increase in the esRAGE/mRAGE ratio in the minigene-transfected cells and in loss of binding of the RNA motif to heterogenous nuclear ribonucleoprotein (hnRNP) H. On the other hand, the artificial introduction of a G-stretch in exon 9B caused a drastic decrease in the esRAGE/mRAGE ratio accompanied by the binding of hnRNP H to the RNA motif. Thus, the G-stretches within exon 9B regulate RAGE alternative splicing via interaction with hnRNP H. The findings should provide a molecular basis for the development of medicines for RAGE-related disorders that could modulate esRAGE/mRAGE ratio.

  12. Eplerenone restores 24-h blood pressure circadian rhythm and reduces advanced glycation end-products in rhesus macaques with spontaneous hypertensive metabolic syndrome.

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    Zhang, Yan; Zheng, Wen; Liu, Yuli; Wang, Jue; Peng, Ying; Shang, Haibao; Hou, Ning; Hu, Xiaomin; Ding, Yi; Xiao, Yao; Wang, Can; Zeng, Fanxin; Mao, Jiaming; Zhang, Jun; Ma, Dongwei; Sun, Xueting; Li, Chuanyun; Xiao, Rui-Ping; Zhang, Xiuqin

    2016-04-01

    Hypertension is often associated with metabolic syndrome (MetS), and serves as a risk factor of MetS and its complications. Blood pressure circadian rhythm in hypertensive patients has been suggested to contribute to cardiovascular consequences and organ damage of hypertension. But circadian changes of BP and their response to drugs have not been clearly investigated in non-human primates (NHPs) of MetS with hypertension. Here, we identified 16 elderly, hypertensive MetS rhesus monkeys from our in-house cohort. With implanted telemetry, we investigate BP changes and its circadian rhythm, together with the effect of antihypertensive drugs on BP and its diurnal fluctuation. MetS hypertensive monkeys displayed higher BP, obesity, glucose intolerance, and dyslipidemia. We also confirmed impaired 24-h BP circadian rhythm in MetS hypertensive monkeys. Importantly, Eplerenone, a mineralocorticoid receptor blocker, exerts multiple beneficial effects in MetS hypertensive monkeys, including BP reduction, 24-h BP circadian rhythm restoration, and decreased plasma concentration of inflammation factors and advanced glycation end-products. In summary, we identified a naturally-developed hypertensive MetS NHP model, which is of great value in the studies on pathogenesis of MetS-associated hypertension and development of novel therapeutic strategies. We also provided multiple novel mechanistic insights of the beneficial effect of Eplerenone on MetS with hypertension.

  13. Soluble Levels of Receptor for Advanced Glycation Endproducts (RAGE) and Progression of Atherosclerosis in Individuals Infected with Human Immunodeficiency Virus: ACTG NWCS 332.

    Science.gov (United States)

    Danoff, Ann; Kendall, Michelle A; Currier, Judith S; Kelesidis, Theodoros; Schmidt, Ann Marie; Aberg, Judith A

    2016-08-01

    Identification of biomarkers and/or mediators of cardiovascular disease (CVD) associated with HIV infection would be of diagnostic and therapeutic value. As soluble receptor for advanced glycation endproducts (sRAGE) and endogenous secretory (esRAGE) have been implicated in vascular complications in other settings, we investigated whether either soluble form of RAGE was associated with changes in carotid intima-media thickness (CIMT) in HIV-infected patients and HIV-uninfected controls. We found no differences in sRAGE, esRAGE, or CIMT among groups at study entry, or in yearly rates of change in sRAGE, esRAGE, or CIMT by HIV-serostatus (all p > 0.10). However, yearly rates of change in sRAGE (p = 0.07) and esRAGE (p < 0.001) were higher in those taking protease inhibitors, and lower baseline esRAGE levels (p = 0.06) were associated with increased odds of CIMT progression in HIV-infected individuals. Although esRAGE was not altered by HIV-serostatus (p = 0.17), its inverse relationship with CIMT progression in HIV-infected patients suggests a possible role as a mediator of CVD in HIV-infected persons.

  14. The receptor for advanced glycation end-products (RAGE) plays a key role in the formation of nanotubes (NTs) between peritoneal mesothelial cells and in murine kidneys.

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    Ranzinger, Julia; Rustom, Amin; Heide, Danijela; Morath, Christian; Schemmer, Peter; Nawroth, Peter P; Zeier, Martin; Schwenger, Vedat

    2014-09-01

    The receptor for advanced glycation end-products (RAGE), a multiligand receptor of the immunoglobulin superfamily, takes part in various inflammatory processes. The role of this receptor in the context of intercellular communication, like nanotube (NT)-mediated interaction, is largely unknown. Here, we use cell cultures of human and murine peritoneal mesothelial cells as well as murine kidneys from wild-type and RAGE knockout mouse models to assess the role of RAGE in NT formation and function. We show that loss of RAGE function results in reduced NT numbers under physiological conditions and demonstrate the involvement of MAP kinase signaling in NT formation. Additionally, we show for the first time the existence of NTs in murine kidney tissue and confirm the correlation of RAGE expression and NT numbers. Under elevated oxidative stress conditions like renal ischemia or peritoneal dialysis, we demonstrate that RAGE absence does not prevent NT formation. Rather, increased NT numbers and attenuated kidney tissue damage could be observed, indicating that, depending on the predominant conditions, RAGE affects NT formation with implications for cellular communication.

  15. Altered Expression of NF- κ B and SP1 after Exposure to Advanced Glycation End-Products and Effects of Neurotrophic Factors in AGEs Exposed Rat Retinas.

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    Bikbova, Guzel; Oshitari, Toshiyuki; Baba, Takayuki; Yamamoto, Shuichi

    2015-01-01

    To determine the effect of advanced glycation end-products (AGEs) on neurite regeneration, and also to determine the regenerative effects of different neurotrophic factors (NTFs) on rat retinal explants, the retinas of SD rats were cultured in three-dimensional collagen gels and incubated in 6 types of media: (1) serum-free control culture media; (2) 100 μg/mL AGEs-BSA media; (3) AGEs-BSA + 100 ng/mL neurotrophin-4 (NT-4) media; (4) AGEs-BSA + 100 ng/mL hepatocyte growth factor media; (5) AGEs-BSA + 100 ng/mL glial cell line-derived neurotrophic factor media; or (6) AGEs-BSA + 100 µM tauroursodeoxycholic acid media. After 7 days, the number of regenerating neurites was counted. The explants were immunostained for nuclear factor-κB (NF-κB) and specificity protein 1 (SP1). Statistical analyses were performed by one-way ANOVA. In retinas incubated with AGEs, the numbers of neurites were fewer than in control. All of the NTFs increased the number of neurites, and the increase was more significant in the NT-4 group. The number of NF-κB and SP1 immunopositive cells was higher in retinas exposed to AGEs than in control. All of the NTFs decreased the number of NF-κB immunopositive cells but did not significantly affect SP1 expression. These results demonstrate the potential of the NTFs as axoprotectants in AGEs exposed retinal neurons.

  16. Vitreous advanced glycation endproducts and α-dicarbonyls in retinal detachment patients with type 2 diabetes mellitus and non-diabetic controls

    Science.gov (United States)

    Mulder, Douwe J.; Schalkwijk, Casper G.; Scheijen, Jean L.; Smit, Andries J.; Los, Leonoor I.

    2017-01-01

    Purpose Advanced glycation endproducts (AGEs) and their precursors α-dicarbonyls are implicated in the progression of diabetic retinopathy. The purpose of this study was to assess AGEs and α-dicarbonyls in the vitreous of patients with type 2 diabetes mellitus (T2DM) with early stages or absence of diabetic retinopathy. Methods We examined vitreous samples obtained during vitrectomy from 31 T2DM patients presenting themselves with rhegmatogenous retinal detachment and compared these to 62 non-diabetic rhegmatogenous retinal detachment patients, matched on age, estimated glomerular filtration rate, smoking, intra-ocular lens implantation, and proliferative vitreoretinopathy. AGEs (pentosidine, Nε-(carboxymethyl)lysine, Nε-(carboxyethyl)lysine, and 5-hydro-5-methylimidazolone) and α-dicarbonyls (3-deoxyglucosone, methylglyoxal, and glyoxal) were measured by ultra performance liquid chromatography or high performance liquid chromatography. Skin autofluorescence was measured by the AGE Reader. Results Mean age was 64 ± 7.6 years for T2DM patients and 63 ± 8.1 years for controls. For T2DM patients, median diabetes duration was 2.2 (0.3–7.4) years. Non-proliferative diabetic retinopathy was present in 1 patient and classified as absent or background retinopathy in 30 patients. Vitreous levels of pentosidine (2.20 vs. 1.59 μmol/mol lysine, p = 0.012) and 3-deoxyglucosone (809 vs. 615 nmol/L, p = 0.001) were significantly elevated in T2DM patients compared to controls. Other AGEs and α-dicarbonyls in the vitreous were not significantly different. There was a trend for increased skin autofluorescence in T2DM patients as compared to controls (p = 0.07). Conclusions Pentosidine and 3-deoxyglucosone concentrations were increased in the vitreous of rhegmatogenous retinal detachment patients with a relatively short duration of diabetes compared to non-diabetic rhegmatogenous retinal detachment patients. PMID:28264049

  17. Angiogenesis impairment in diabetes: role of methylglyoxal-induced receptor for advanced glycation endproducts, autophagy and vascular endothelial growth factor receptor 2.

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    Hongtao Liu

    Full Text Available Diabetes impairs physiological angiogenesis by molecular mechanisms that are not fully understood. Methylglyoxal (MGO, a metabolite of glycolysis, is increased in patients with diabetes. This study defined the role of MGO in angiogenesis impairment and tested the mechanism in diabetic animals. Endothelial cells and mouse aortas were subjected to Western blot analysis of vascular endothelial growth factor receptor 2 (VEGFR2 protein levels and angiogenesis evaluation by endothelial cell tube formation/migration and aortic ring assays. Incubation with MGO reduced VEGFR2 protein, but not mRNA, levels in a time and dose dependent manner. Genetic knockdown of the receptor for advanced glycation endproducts (RAGE attenuated the reduction of VEGFR2. Overexpression of Glyoxalase 1, the enzyme that detoxifies MGO, reduced the MGO-protein adducts and prevented VEGFR2 reduction. The VEGFR2 reduction was associated with impaired angiogenesis. Suppression of autophagy either by inhibitors or siRNA, but not of the proteasome and caspase, normalized both the VEGFR2 protein levels and angiogenesis. Conversely, induction of autophagy either by rapamycin or overexpression of LC3 and Beclin-1 reduced VEGFR2 and angiogenesis. MGO increased endothelial LC3B and Beclin-1, markers of autophagy, which were accompanied by an increase of both autophagic flux (LC3 punctae and co-immunoprecipitation of VEGFR2 with LC3. Pharmacological or genetic suppression of peroxynitrite (ONOO(- generation not only blocked the autophagy but also reversed the reduction of VEGFR2 and angiogenesis. Like MGO-treated aortas from normglycemic C57BL/6J mice, aortas from diabetic db/db and Akita mice presented reductions of angiogenesis or VEGFR2. Administration of either autophagy inhibitor ex vivo or superoxide scavenger in vivo abolished the reductions. Taken together, MGO reduces endothelial angiogenesis through RAGE-mediated, ONOO(-dependent and autophagy-induced VEGFR2 degradation, which

  18. Scopoletin Protects against Methylglyoxal-Induced Hyperglycemia and Insulin Resistance Mediated by Suppression of Advanced Glycation Endproducts (AGEs Generation and Anti-Glycation

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    Wen-Chang Chang

    2015-02-01

    Full Text Available Recently, several types of foods and drinks, including coffee, cream, and cake, have been found to result in high methylglyoxal (MG levels in the plasma, thus causing both nutritional and health concerns. MG can be metabolized by phase-II enzymes in liver through the positive regulation of nuclear factor-erythroid 2-related factor 2 (Nrf2. In this study, we investigated the ability of scopoletin (SP to protect against MG-induced hyperglycemia and insulin resistance. Recently, SP was shown to be a peroxisome proliferator-activated receptor-γ activator to elevate insulin sensitivity. We investigated the effects of oral administration of SP on the metabolic, biochemical, and molecular abnormalities characteristic of type 2 diabetes in MG-treated Wistar rats to understand the potential mechanism of scopoletin for diabetes protection. Our results suggested that SP activated Nrf2 by Ser40 phosphorylation, resulting in the metabolism of MG into d-lactic acid and the inhibition of AGEs generation, which reduced the accumulation of AGEs in the livers of MG-induced rats. In this manner, SP improved the results of the oral glucose tolerance test and dyslipidemia. Moreover, SP also increased the plasma translocation of glucose transporter-2 and promoted Akt phosphorylation caused by insulin treatment in MG-treated FL83B hepatocytes. In contrast, SP effectively suppressed protein tyrosine phosphatase 1B (PTP1B expression, thereby alleviating insulin resistance. These findings suggest that SP acts as an anti-glycation and anti-diabetic agent, and thus has therapeutic potential for the prevention of diabetes.

  19. Assessment of the concentrations of various advanced glycation end-products in beverages and foods that are commonly consumed in Japan.

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    Masayoshi Takeuchi

    Full Text Available Dietary consumption has recently been identified as a major environmental source of pro-inflammatory advanced glycation end-products (AGEs in humans. It is disputed whether dietary AGEs represent a risk to human health. Nε-(carboxymethyllysine (CML, a representative AGE compound found in food, has been suggested to make a significant contribution to circulating CML levels. However, recent studies have found that the dietary intake of AGEs is not associated with plasma CML concentrations. We have shown that the serum levels of glyceraldehyde-derived AGEs (Glycer-AGEs, but not hemoglobin A1c, glucose-derived AGEs (Glu-AGEs, or CML, could be used as biomarkers for predicting the progression of atherosclerosis and future cardiovascular events. We also detected the production/accumulation of Glycer-AGEs in normal rats administered Glu-AGE-rich beverages. Therefore, we assessed the concentrations of various AGEs in a total of 1,650 beverages and foods that are commonly consumed in Japan. The concentrations of four kinds of AGEs (Glu-AGEs, fructose-derived AGEs (Fru-AGEs, CML, and Glycer-AGEs were measured with competitive enzyme-linked immunosorbent assays involving immunoaffinity-purified specific antibodies. The results of the latter assays indicated that Glu-AGEs and Fru-AGEs (especially Glu-AGEs, but not CML or Glycer-AGEs, are present at appreciable levels in beverages and foods that are commonly consumed by Japanese. Glu-AGEs, Fru-AGEs, CML, and Glycer-AGEs exhibited concentrations of ≥85%, 2-12%, <3%, and trace amounts in the examined beverages and ≥82%, 5-15%, <3%, and trace amounts in the tested foods, respectively. The results of the present study indicate that some lactic acid bacteria beverages, carbonated drinks, sugar-sweetened fruit drinks, sports drinks, mixed fruit juices, confectionery (snacks, dried fruits, cakes, cereals, and prepared foods contain markedly higher Glu-AGE levels than other classes of beverages and foods. We

  20. Parainflammation associated with advanced glycation endproduct stimulation of RPE in vitro: implications for age-related degenerative diseases of the eye.

    Science.gov (United States)

    Lin, Tony; Walker, Gregory Brett; Kurji, Khaliq; Fang, Edward; Law, Geoffrey; Prasad, Shiv S; Kojic, Luba; Cao, Sijia; White, Valerie; Cui, Jing Z; Matsubara, Joanne A

    2013-06-01

    Age related macular degeneration (AMD) is one of the leading causes of blindness in Western society. A hallmark of early stage AMD are drusen, extracellular deposits that accumulate in the outer retina. Advanced glycation endproducts (AGE) accumulate with aging and are linked to several age-related diseases such as Alzheimer's disease, osteoarthritis, atherosclerosis and AMD. AGE deposits are found in drusen and in Bruch's membrane of the eye and several studies have suggested its role in promoting oxidative stress, apoptosis and lipofuscin accumulation. Recently, complement activation and chronic inflammation have been implicated in the pathogenesis of AMD. While AGEs have been shown to promote inflammation in other diseases, whether it plays a similar role in AMD is not known. This study investigates the effects of AGE stimulation on pro- and anti-inflammatory pathways in primary culture of human retinal pigment epithelial cells (RPE). Differential gene expression studies revealed a total of 41 up- and 18 down-regulated RPE genes in response to AGE stimulation. These genes fell into three categories as assessed by gene set enrichment analysis (GSEA). The main categories were inflammation (interferon-induced, immune response) and proteasome degradation, followed by caspase signaling. Using suspension array technology, protein levels of secreted cytokines and growth factors were also examined. Anti-inflammatory cytokines including IL10, IL1ra and IL9 were all overexpressed. Pro-inflammatory cytokines including IL4, IL15 and IFN-γ were overexpressed, while other pro-inflammatory cytokines including IL8, MCP1, IP10 were underexpressed after AGE stimulation, suggesting a para-inflammation state of the RPE under these conditions. Levels of mRNA of chemokine, CXCL11, and viperin, RSAD2, were up-regulated and may play a role in driving the inflammatory response via the NF-kB and JAK-STAT pathways. CXCL11 was strongly immunoreactive and associated with drusen in the AMD

  1. Advanced lipoxidation end-products.

    Science.gov (United States)

    Pamplona, Reinald

    2011-06-30

    Chemical and nonenzymatic molecular modifications induced by reactive carbonyl species (RCS) generated by peroxidation of membrane phospholipids acyl chains play a dual role as signaling molecules and as mediators of the aging process. Cytotoxic effects of RCS are due to their capacity to react with cellular constituents, forming advanced lipoxidation end-products (ALEs). Reactive carbonyl compounds are stable and can diffuse within or even escape from the cell and attack targets far from the site of formation. The consequent loss of function and structural integrity of modified biomolecules can have a wide range of downstream functional consequences and may be the cause of subsequent cellular dysfunctions and tissue damage.

  2. Hyperoside Downregulates the Receptor for Advanced Glycation End Products (RAGE and Promotes Proliferation in ECV304 Cells via the c-Jun N-Terminal Kinases (JNK Pathway Following Stimulation by Advanced Glycation End-Products In Vitro

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    Zhengyu Zhang

    2013-11-01

    Full Text Available Hyperoside is a major active constituent in many medicinal plants which are traditionally used in Chinese medicines for their neuroprotective, anti-inflammatory and antioxidative effects. The molecular mechanisms underlying these effects are unknown. In this study, quiescent ECV304 cells were treated in vitro with advanced glycation end products (AGEs in the presence or absence of hyperoside. The results demonstrated that AGEs induced c-Jun N-terminal kinases (JNK activation and apoptosis in ECV304 cells. Hyperoside inhibited these effects and promoted ECV304 cell proliferation. Furthermore, hyperoside significantly inhibited RAGE expression in AGE-stimulated ECV304 cells, whereas knockdown of RAGE inhibited AGE-induced JNK activation. These results suggested that AGEs may promote JNK activation, leading to viability inhibition of ECV304 cells via the RAGE signaling pathway. These effects could be inhibited by hyperoside. Our findings suggest a novel role for hyperoside in the treatment and prevention of diabetes.

  3. Rosiglitazone inhibits expression of acyl-coenzyme A:cholesterol acyltransferase-1 in THP-1 macrophages induced by advanced glycation end-products

    Institute of Scientific and Technical Information of China (English)

    Yang Qihong; Xu Qiang; Zhang Hong; Si Liangyi

    2008-01-01

    Objective: To investigate the effects of rosiglitazone, a synthetic ligand of peroxisome proliferators-activated receptor gamma (PPARγ), on the expression of acyl-coenzyme A: cholesterol acyltransferase-1 (ACAT-1) in phorbol myristate acetate (PMA)-pretreated THP-1 cells after the inducement of advanced glycation end products (AGEs). Methods: After THP-1 cells were cultured in the presence of 0.1 umol/L PMA for 72 h to induce phagocytic differentiation, the obtained THP-1 macrophages were treated with rosiglitazone for 4 h at different concentrations (1,5 or 10 μmol/L) and then exposed to AGEs-modified bovine serum albumin (AGEs-BSA) for 24 h at a concentration of 200 mg/L. Reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis were performed to detect the mRNA and protein expressions of ACAT-1 respectively. Results: Administration of AGEs-BSA (200 mg/L) into the THP-1 macrophages resulted in up-regulation of ACAT-1 at mRNA and protein levels when compared with the expressions in macrophages incubated with serum-free RPM11640. Pretreatment of rosiglitazone inhibited significantly the increased expression of ACAT-1 induced by AGEs-BSA in a concentration-dependent manner. Conclusion: PPARγ activation by rosiglitazone down-regulates ACAT-1 expression induced by AGEs in THP-1 macrophages, which might provide a new way for treating atherogenesis in diabetic patients.

  4. Pomegranate (Punicagranatum) juice decreases lipid peroxidation, but has no effect on plasma advanced glycated end-products in adults with type 2 diabetes: a randomized double-blind clinical trial

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    Sohrab, Golbon; Angoorani, Pooneh; Tohidi, Maryam; Tabibi, Hadi; Kimiagar, Masoud; Nasrollahzadeh, Javad

    2015-01-01

    Introduction Diabetes mellitus characterized by hyperglycemia could increase oxidative stress and formation of advanced glycated end-products (AGEs), which contribute to diabetic complications. The purpose of this study was to assess the effect of pomegranate juice (PJ) containing natural antioxidant on lipid peroxidation and plasma AGEs in patients with type 2 diabetes (T2D). Materials and methods In a randomized, double-blind, placebo-controlled trial, 44 patients (age range 56±6.8 years), T2D were randomly assigned to one of two groups: group A (PJ, n=22) and group B (Placebo, n=22). At the baseline and the end of 12-week intervention, biochemical markers including fasting plasma glucose, insulin, oxidative stress, and AGE markers including carboxy methyl lysine (CML) and pentosidine were assayed. Results At baseline, there were no significant differences in plasma total antioxidant capacity (TAC) levels between the two groups, but malondialdehyde (MDA) decreased levels were significantly different (P<0.001). After 12 weeks of intervention, TAC increased (P<0.05) and MDA decreased (P<0.01) in the PJ group when compared with the placebo group. However, no significant differences were observed in plasma concentration of CML and pentosidine between the two groups. Conclusions The study showed that PJ decreases lipid peroxidation. Therefore, PJ consumption may delay onset of T2D complications related to oxidative stress. PMID:26355954

  5. Pomegranate (Punicagranatum juice decreases lipid peroxidation, but has no effect on plasma advanced glycated end-products in adults with type 2 diabetes: a randomized double-blind clinical trial

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    Golbon Sohrab

    2015-09-01

    Full Text Available Introduction: Diabetes mellitus characterized by hyperglycemia could increase oxidative stress and formation of advanced glycated end-products (AGEs, which contribute to diabetic complications. The purpose of this study was to assess the effect of pomegranate juice (PJ containing natural antioxidant on lipid peroxidation and plasma AGEs in patients with type 2 diabetes (T2D. Materials and methods: In a randomized, double-blind, placebo-controlled trial, 44 patients (age range 56±6.8 years, T2D were randomly assigned to one of two groups: group A (PJ, n=22 and group B (Placebo, n=22. At the baseline and the end of 12-week intervention, biochemical markers including fasting plasma glucose, insulin, oxidative stress, and AGE markers including carboxy methyl lysine (CML and pentosidine were assayed. Results: At baseline, there were no significant differences in plasma total antioxidant capacity (TAC levels between the two groups, but malondialdehyde (MDA decreased levels were significantly different (P<0.001. After 12 weeks of intervention, TAC increased (P<0.05 and MDA decreased (P<0.01 in the PJ group when compared with the placebo group. However, no significant differences were observed in plasma concentration of CML and pentosidine between the two groups. Conclusions: The study showed that PJ decreases lipid peroxidation. Therefore, PJ consumption may delay onset of T2D complications related to oxidative stress.

  6. Vascular Effects of Advanced Glycation End-Products: Content of Immunohistochemically Detected AGEs in Radial Artery Samples as a Predictor for Arterial Calcification and Cardiovascular Risk in Asymptomatic Patients with Chronic Kidney Disease

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    Katarzyna Janda

    2015-01-01

    Full Text Available Objectives. Our aim was to determine whether vascular deposition of advanced glycation end-products (AGEs is associated with arterial calcification and cardiovascular mortality in chronic kidney disease (CKD patients and to assess the relationships between vascular content of AGEs and selected clinical and biochemical parameters. Materials and Methods. The study comprised 54 CKD patients (33 hemodialyzed, 21 predialyzed. Examined parameters included BMI, incidence of diabetes, plasma fasting glucose, AGEs, soluble receptor for AGEs and 2,2-diphenyl-1-picrylhydrazyl (DPPH scavenging, serum C-reactive protein (hsCRP, plasminogen activator inhibitor-1 (PAI-1, and fetuin-A. Fragments of radial artery obtained during creation of hemodialysis access were stained for calcifications using alizarin red. AGEs deposits were identified immunohistochemically and their relative content was quantified. Results. Vascular content of AGEs was positively correlated with BMI, hsCRP, fetuin-A, PAI-1, and DPPH scavenging in simple regression; only fetuin-A was an independent predictor in multiple regression. There was a significant positive trend in the intensity of AGEs immunostaining among patients with grades 1, 2, and 3 calcifications. AGEs immunostaining intensity predicted 3-year cardiovascular mortality irrespective of patient’s age. Conclusions. The present study demonstrates an involvement of AGEs in the development of medial arterial calcification and the impact of arterial AGE deposition on cardiovascular mortality in CKD patients.

  7. Skin autofluorescence, a marker of advanced glycation end products and oxidative stress, is increased in recently preeclamptic women

    NARCIS (Netherlands)

    Blaauw, Judith; Smit, Andries J.; van Pampus, Maria G.; van Doormaal, Jasper J.; Aarnoudse, Jan G.; Rakhorst, Gerhard; Graaff, Reindert

    2006-01-01

    Objective: Advanced glycation end-products are considered to be markers of oxidative stress and to be involved in the atherosclerotic process. We investigated skin autofluorescence, which reflected advanced glycation end-product accumulation, in recently preeclamptic women and its relationship with

  8. Produtos da glicação avançada dietéticos e as complicações crônicas do diabetes Dietetics advanced glycation end-products and chronic complications of diabetes

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    Júnia Helena Porto Barbosa

    2009-02-01

    a conduta terapêutica, concorrendo para a melhoria da qualidade de vida dos portadores dessa enfermidade.The generation of advanced glycation end products is one of the principal mechanisms that lead to the pathologies associated with diabetes mellitus, which include cardiopathy, retinopathy, neuropathy and nephropathy. The objective of this revision is to analyse the role of the advanced glycation end products present in food as intermediaries of diabetic complications, presenting strategies to reduce their ingestion. For this purpose, research was carried out in databases of publications of the area, for the last 15 years, taking into account revision, experimental and clinical studies. Advanced glycation end products are a heterogenous group of molecules coming from non-enzymatic reactions between amino and carbonyl groups, examples being carboxymethyllisine and pentosidine found in food and in vivo. The advanced glycation end products ingested are absorbed and, along with endogenous advanced glycation end-products, promote the progression of the complications of diabetes. There is a direct correlation between advanced glycation end products consumption and blood concentration. Their restriction in food results in the suppression of serum levels of the markers of vascular disease and the intermediaries of inflammation directly involved in the development of diabetic degenerations. The current dietary orientations are concentrated on the proportion of nutrients and on energetic restriction. The risk of ingestion of advanced glycation end products formed during the processing of food should be taken in consideration. It is simply recommended that in the preparation of food, the use of low temperatures for short periods, in the presence of water, has important effects in the prevention of the complications of diabetes. The study of the mechanisms involved in the generation of advanced glycation end products and the antiglycation properties of compounds presented in

  9. Inhibition of Advanced Glycation End-Product Formation by Origanum majorana L. In Vitro and in Streptozotocin-Induced Diabetic Rats

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    Perez Gutierrez, Rosa Martha

    2012-01-01

    The development of AGE inhibitors is considered to have therapeutic potential in patients with diabetes diseases. The aim of the present study was investigate the effect of methanolic extract of the leaves of Origanum majorana (OM) used as spice in many countries on AGEs formation. In vitro studies indicated a significant inhibitory effects on the formation of AGEs. Their antiglycation activities were not only brought about by their antioxidant activities but also related to their trapping abilities of reactive carbonyl species such as methylglyoxal, an intermediate reactive carbonyl of AGE formation. The results demonstrate that OM have significant effects on in vitro AGE formation, and the glycation inhibitory activity was more effectively than those obtained using as standard antiglycation agent aminoguanidine. OM is a potent agent for protecting LDL against oxidation and glycation. Treatment of streptozotocin-diabetic mice with OM and glibenclamide for 28 days had beneficial effects on renal metabolic abnormalities including glucose level and AGEs formation. Diabetic mice showed increase in tail tendon collagen, glycated collagen linked fluorescence and reduction in pepsin digestion. Treatment with OM improved these parameters when compared to diabetic control and glibenclamide. PMID:23008741

  10. Inhibition of Advanced Glycation End-Product Formation by Origanum majorana L. In Vitro and in Streptozotocin-Induced Diabetic Rats

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    Rosa Martha Perez Gutierrez

    2012-01-01

    Full Text Available The development of AGE inhibitors is considered to have therapeutic potential in patients with diabetes diseases. The aim of the present study was investigate the effect of methanolic extract of the leaves of Origanum majorana (OM used as spice in many countries on AGEs formation. In vitro studies indicated a significant inhibitory effects on the formation of AGEs. Their antiglycation activities were not only brought about by their antioxidant activities but also related to their trapping abilities of reactive carbonyl species such as methylglyoxal, an intermediate reactive carbonyl of AGE formation. The results demonstrate that OM have significant effects on in vitro AGE formation, and the glycation inhibitory activity was more effectively than those obtained using as standard antiglycation agent aminoguanidine. OM is a potent agent for protecting LDL against oxidation and glycation. Treatment of streptozotocin-diabetic mice with OM and glibenclamide for 28 days had beneficial effects on renal metabolic abnormalities including glucose level and AGEs formation. Diabetic mice showed increase in tail tendon collagen, glycated collagen linked fluorescence and reduction in pepsin digestion. Treatment with OM improved these parameters when compared to diabetic control and glibenclamide.

  11. 晚期糖基化终末产物在光老化皮肤中的表达%Expression of advanced glycation end-products in photoaging skin

    Institute of Scientific and Technical Information of China (English)

    郑瑞; 董志姗; 李灵敏; 张嘉; 郝建春; 冯艳

    2014-01-01

    Objective To detect the expression of advanced glycation end-products (AGEs) in the sun exposure and non-exposure skin,to observe the elastic protein in the same location,and to explore the relationship between non-enzymatic glycation reactions and,photo-aging skin morphological changes.Methods In the exposure and non-exposure specimens from 30 patients,elastic fibers were stained with Gomori staining,and immunohistochemistry for AGEs was performed.Results AGEs expressed clearly positive in all elastic fibers of degeneration markedly (+ + above) of exposure skin,and appeared line-like in markedly(+ + above)elastic fibers.While in all non-exposure skin,AGEs expressed negative.In the exposure skin with middle or old age,compared with non-exposure skin,AGEs expressed more and elastic fibers were hyperplasia with thickening,curling and irregular distribution.The skin parts of AGEs expressed accorded with where elastic fibers degenerated.Conclusions Ultraviolet radiation can induce denaturation of elastic fibers and non-enzymatic glycation may contribute to the mechanism of skin photo-aging.%目的 观察光暴露及非光暴露部位的皮肤组织中晚期糖基化终末产物(AGEs)的表达特点,同时对比观察弹性纤维的形态改变,探讨非酶糖基化反应(non-enzymatic glycation,NEG)与光老化皮肤形态学改变的关系.方法 对30例不同年龄的光暴露和非光暴露皮肤标本,采用醛品红法染色观察弹性纤维的变化及SP免疫组织化学检测AGEs表达.结果 光暴露部位弹力纤维变性分级++以上标本中,均有明显的AGEs表达;++以下标本有线状分布的AGEs表达.非光暴露标本中,AGEs表达均为阴性.同一年龄,光暴露和非光暴露标本中,光暴露部位的AGEs的表达明显高于非光暴露部位,同时出现弹性纤维明显增多、增粗,出现扭曲、不规则分布.AGEs的表达同弹性纤维发生变性部位基本相符.结论 NEG反应在皮肤光老化的发生机制中可能有一定的作用.

  12. Intra-coronary administration of soluble receptor for advanced glycation end-products attenuates cardiac remodeling with decreased myocardial transforming growth factor-β1 expression and fibrosis in minipigs with ischemia-reperfusion injury

    Institute of Scientific and Technical Information of China (English)

    LU Lin; SHEN Wei-feng; ZHANG Qi; XU Yan; ZHU Zheng-bin; GENG Liang; WANG Ling-jie; JIN Cao; CHEN Qiu-jing; Ann Marie Schmidt

    2010-01-01

    Background The cardioprotective effects of soluble receptor for advanced glycation end-products (sRAGE) have not been evaluated in large animals and the underlying mechanisms are not fully understood. This study aimed to evaluate the effects of intra-coronary administration of sRAGE on left ventricular function and myocardial remodeling in a porcine model of ischemia-reperfusion (I/R) injury. Methods Ten male minipigs with I/R injury were randomly allocated to receive intra-coronary administration of sRAGE (sRAGE group, n=5) or saline (control group, n=5). Echocardiography was performed before and 2 months after infarction. Myocardial expression of transforming growth factor (TGF)-β1was determined by immunohistochemistry and fibrosis was evaluated by Sirius red staining. Results As compared with the baseline values in the control animals, left ventricular end-diastolic volume (from (19.5 5.1) to (32.3 5.6) ml, P <0.05) and end-systolic volume (from (8.3 3.2) to (15.2 4.1) ml, P <0.05) were significantly increased, whereas ejection fraction was decreased (from (61.6 13.3)% to (50.2 11.9)%, P<0.05). No obvious change in these parameters was observed in the sRAGE group. Myocardial expression of TGF-β1 was significantly elevated in the infarct and non-infarct regions in the control group, as compared with sRAGE group (both P<0.01). Fibrotic lesions were consistently more prominent in the infarct region of the myocardium in the control animals (P<0.05). Conclusion Intra-coronary sRAGE administration attenuates RAGE-mediated myocardial fibrosis and I/R injury through a TGF-β1-dependent mechanism, suggesting a clinical potential in treating RAGE/ligand-associated cardiovascular diseases.

  13. Expression of advanced glycation end-products on sun-exposed and non-exposed cutaneous sites during the ageing process in humans.

    Directory of Open Access Journals (Sweden)

    Maria Crisan

    Full Text Available The glycation process is involved in both the intrinsic (individual, genetic and extrinsic (ultraviolet light, polution and lifestyle aging processes, and can be quantified at the epidermal or dermal level by histological, immunohistochemical (IHC, or imagistic methods. Our study is focused on a histological and immunohistological comparison of sun-protected regions versus sun-exposed regions from different age groups of skin phototype III subjects, related to the aging process. Skin samples collected from non-protected and UV protected regions of four experimental groups with different ages, were studied using histology and IHC methods for AGE-CML [N(epsilon-(carboxymethyllysine]. A semi-quantitative assessment of the CML expression in the microvascular endothelium and dermal fibroblasts was performed. The Pearson one-way ANOVA was used to compare data between the groups. In the dermis of sun-exposed skin, the number and the intensity of CML positive cells in both fibroblasts and endothelial cells (p<0.05 was higher compared to sun-protected skin, and was significantly increased in older patients. The sun-exposed areas had a more than 10% higher AGE-CML score than the protected areas. No statistically significant correlation was observed between the histological score and the IHC expression of CML. We concluded that in healthy integument, the accumulation of final glycation products increases with age and is amplified by ultraviolet exposure. The study provides new knowledge on differences of AGE-CML between age groups and protected and unprotected areas and emphasizes that endothelium and perivascular area are most affected, justifying combined topical and systemic therapies.

  14. Injury of cortical neurons is caused by the advanced glycation end products-mediated pathway

    Institute of Scientific and Technical Information of China (English)

    Ying Xing; Xu Zhang; Xiangfu Song; Zhongwen Lv; Lingling Hou; Fei Li

    2013-01-01

    Advanced glycation end products lead to cell apoptosis, and cause cell death by increasing endoplasmic reticulum stress. Advanced glycation end products alone may also directly cause damage to tissues and cells, but the precise mechanism remains unknown. This study used primary cultures of rat cerebral cortex neurons, and treated cells with different concentrations of glycation end products (50, 100, 200, 400 mg/L), and with an antibody for the receptor of advanced glycation end products before and after treatment with advanced glycation end products. The results showed that with increasing concentrations of glycation end products, free radical content increased in neurons, and the number of apoptotic cells increased in a dose-dependent manner. Before and after treatment of advanced glycation end products, the addition of the antibody against advanced glycation end-products markedly reduced hydroxyl free radicals, malondialdehyde levels, and inhibited cell apoptosis. This result indicated that the antibody for receptor of advanced glycation end-products in neurons from the rat cerebral cortex can reduce glycation end product-induced oxidative stress damage by suppressing glycation end product receptors. Overall, our study confirms that the advanced glycation end products-advanced glycation end products receptor pathway may be the main signaling pathway leading to neuronal damage.

  15. Consequences of Advanced Glycation End Products Accumulation in Chronic Kidney Disease and Clinical Usefulness of Their Assessment Using a Non-invasive Technique - Skin Autofluorescence.

    Science.gov (United States)

    Oleniuc, Mihaela; Secara, Irina; Onofriescu, Mihai; Hogas, Simona; Voroneanu, Luminita; Siriopol, Dimitrie; Covic, Adrian

    2011-10-01

    Accelerated formation and accumulation of advanced glycation end-products occur under circumstances of increased supply of substrates such as hyperglycaemic or oxidative stress and in age-related and chronic diseases like diabetes mellitus, chronic renal failure, neurodegenerative diseases, osteoarthritis and also non-diabetic atherosclerosis and chronic heart failure. Advanced glycation end-products accumulation occurs especially on long-lived proteins such as collagen in the skin and in vascular basement membranes leading to vascular damage. Adequate renal clearance capacity is an important factor in the effective removal of advanced glycation end-products. The Autofluorescence Reader was developed as a marker, representative for tissue advanced glycation end-products accumulation, easily applicable in a clinical setting, initially for predicting diabetes related complications. Studies have already shown a relationship between skin autofluorescence and diabetes complications, as well as its predictive value for total and cardiovascular mortality in type 2 diabetes. Moreover skin autofluorescence was demonstrated to be superior to Haemoglobin A1c and other conventional risk factors. Advanced glycation end-products have been proposed as a novel factor involved in the development and progression of chronic heart failure. Assessment of advanced glycation end-products accumulation in end-stage renal disease and undergoing renal replacement therapies patients has become of great importance. Cardiovascular and connective tissue disorders are very common in patients with end-stage renal disease, and the accumulation of advanced glycation end-products is significantly increased in these patients. Mortality is markedly increased in patients with decreased kidney function, particularly in patients with end-stage renal disease. Skin advanced glycation end-products levels are strong predictors of survival in haemodialysis patients independent of other established risk factors

  16. 糖基化终产物受体在大鼠牙周膜成纤维细胞中的表达%Expression of receptor for advanced glycation end-product in rat periodontal ligament fibroblasts

    Institute of Scientific and Technical Information of China (English)

    邓天政; 吕晶; 冯岩; 李冬霞; 刘冰; 逄键梁; 柯杰

    2012-01-01

    Objective To detect expression of receptor for advanced glycation end products (RAGE) produced by human periodontal ligament fibroblasts ( PDL) cultured in vitro. Methods To collect rat periodontal ligament firbroblast induced by 50, 100, 200 mg/L advanced glycation end products-bovine serum albumin ( AGE-BSA) 200 mg/L BSA and blank control in DMEM in vitro, which were group A, B, C, D, E respectively. Detect mRNA of RAGE using RT-PCR and protein expression using immunohistochemistry. Results Immunohistochemistry showed the protein expression ofRAGE in group A, B, C, and the expression level elevated with the increase of AGE-BSA concentration. Group D and E did not express RAGE protein. RT-PCR proved the gene of RAGE expresses in group A, B, C. Group D expressed a little, group E did not express. Conclusion RAGE can be produced by PDL cultured in vitro induced by AGE-BSA.%目的 研究体外培养大鼠牙周膜成纤维细胞在糖基化终产物诱导下糖基化终产物受体( receptor for advanced glycation end-product,RAGE)的表达情况.方法 收集第三代体外培养的大鼠牙周膜成纤维细胞,在含有终浓度为50、100、200 mg/L的糖基化牛血清白蛋白、200 ms/L的牛血清白蛋白以及不含上述蛋白成分培养基内孵育48h,分别设为A组、B组、C组、D组、E组.免疫组织化学法、反转录-聚合酶链反应(reverse transcription-polymerase chain reaction,RT-PCR)检测细胞内RAGE蛋白及mRNA表达.结果 免疫组织化学结果显示A、B、C组中牙周膜成纤维细胞内RAGE蛋白表达均为阳性,且随浓度增高,表达强度略有增强,而D及E组无表达;RT-PCR检测发现A、B、C组RAGE mRNA均表达且表达强度随浓度增高而增强,D组有少量表达,E组不表达.结论 体外培养的牙周膜成纤维细胞在糖基化终产物诱导下能够表达RAGE.

  17. The relationship between high mobility group-B1/receptor for advanced glycation endproducts and Alzheimer's disease%高迁移率组蛋白1/晚期糖基化终末产物受体与阿尔茨海默病

    Institute of Scientific and Technical Information of China (English)

    耿丽颖; 王珊; 王斌斌; 孙雪娇; 张国华

    2016-01-01

    随着时代的发展、科技的进步,人们的物质文化水平也逐步提高,除了对物质的追求之外,对精神方面的享受也更加注重,然而阿尔茨海默病(AD)却大大地影响了人们晚年的生活质量.阿尔茨海默病可能的发病机制包括:Aβ沉积、tau蛋白过度磷酸化、神经血管功能紊乱、细胞周期异常、炎症、氧化应激、线粒体功能障碍.而由Aβ沉积引起的炎性反应在其发病机制中至关重要.高迁移率组蛋白1(HMGB1)及晚期糖基化终末产物受体(RAGE)均可参与Aβ沉积而在阿尔茨海默病中发挥作用,两者结合后也可引起炎症反应等效应,促进阿尔茨海默病的进展.本文就HMGB1/RAGE及其与阿尔茨海默病的相关研究做一综述.%As the development of the times and scientific progress,people's material culture has been enhanced.We pay attention to not only the material pursuing but also spiritual enjoyment.However,Alzheimer's disease affects the quality of late-life significantly.Congnitive disorder is one clinical symptom of Alzheimer's disease,which influences people's later life the most.β-amyloid (Aβ) plaques accumulation,tau protein hyperphosphorylation,nerve vascular dysfunction,abnormal cell cycle,inflammation,oxidative stress,and mitochondrial disorder may be the pathogenesis of Alzheimer's disease.The inflammation of Alzheimer's disease can be caused by the nervous lesions that are generated by the inflammatory mediator released by activated neurogliocyte around Aβ.High mobility group-B1 (HMGB1) and receptor for advanced glycation endproducts (RAGE) are closely related to the inflammation.It may also promote the progresses of Alzheimer;s disease,if HMGB1 is combined with RAGE.This review aims to elaborate the relationship between HMGB1/RAGE and Alzheimer's disease.

  18. 代谢综合征患者可溶性晚期糖基化终产物受体与动脉僵硬度的关系%Correlation between soluble receptor for advanced glycation endproducts and arterial stiffness in patients with metabolic syndrome

    Institute of Scientific and Technical Information of China (English)

    田朝伟; 王丽; 晋荣; 钟赟; 刘世明

    2015-01-01

    Objective investigate the correlation between plasma soluble receptor for advanced glycation endproducts (sRAGE) and arterial stiffness in patients with different types of metabolic syndrome (MS).Methods A total of 180 subjects were drawn from a epidemiologic follow-up study,including 60 cases non-metabolic syndrome (NMS),60 cases metabolic syndrome without diabetes mellitus (NDMMS),60 cases metabolic syndrome with diabetes mellitus (DMMS).Carotid femoral arterial pulse wave velocity (CFPWV) was assessed by the French KangPuLe atherosclerosis measurement instrument,and plasma sRAGE levels were measured by ELISA.Comparison of mean in multiple groups was conducted by analysis of variance.Multivariate analysis was done with multiple linear stepwise regression analysis.P < 0.05 was considered as statistically significant difference.Results Compared with NMS group,plasma sRAGE levels were significantly lower in DMMS and NDMMS groups [(635.07 ± 229.20) pg/mL vs.(671.17 ± 358.16) pg/mL vs.(992.99 ± 427.83) pg/mL,P =0.001].CFPWV of DMMS group was significantly higher than that of NMDMS and NMS groups (14.22 ±3.14) m/s vs.(12.15 ±2.79) m/s vs.(11.66 ± 2.52) m/s,P =0.002).Plasma sRAGE level was negatively correlated with CFPWV (r =-0.278,P =0.005).(3) Multiple linear regression analysis demonstrated that age (β =-0.091,95% CI-0.096 ~-0.095,P =0.031),HDL-C (β =1.295,95% CI 1.231 ~ 1.360,P =0.022) and sRAGE (β =0.119,95% CI 0.118 ~ 0.130,P =0.032) had a significant effect on CFPWV.Conclusions The increased arterial stiffness is closely related to the discreased plasma sRAGE levels in MS.Plasma sRAGE maybe a novel target for vascular disease prevention and treatment in patients with metabolic syndrome.%目的 探讨在不同类型代谢综合征(metabolic syndrome,MS)患者血浆中可溶性晚期糖基化终产物受体(soluble receptor for advanced glycation endproducts,sRAGE)与动脉僵硬度的关系.方法 采用病例对照的方

  19. Simple non-invasive assessment of advanced glycation endproduct accumulation

    NARCIS (Netherlands)

    Meerwaldt, R; Graaff, R; Links, TP; Jager, JJ; Alderson, NL; Thorpe, [No Value; Baynes, JW; Gans, ROB; Smit, AJ

    2004-01-01

    Aims/hypothesis. The accumulation of AGE is thought to play a role in the pathogenesis of chronic complications of diabetes mellitus and renal failure. All current measurements of AGE accumulation require invasive sampling. We exploited the fact that several AGE exhibit autofluorescence to develop a

  20. 黄连多糖对AGEs诱导内皮细胞增殖及其受体表达的作用研究%Effects of Polysaccharides from Coptis Chinensis on HUVECs Proliferation Induced by Advanced Glycation Endproducts and Expression of Its Receptor

    Institute of Scientific and Technical Information of China (English)

    尹登科; 杨晔; 陈松; 李云; 高向东

    2012-01-01

    To study the effects of Coptis Chinensis polysaccharide (CCP) on HUVECs proliferation induced by advanced glycation endproducts(AGEs) and the expression of the receptor for AGEs(RAGE) ,the total CCP was prepared by water extraction, depro-teinized by method of sevag,and alcohol precipitation. HUVECs with 80% confluent were divided into six groups as control (without treatment) ,BSA group ( 200 μg /mL) , AGEs group(200 μg/mL, protein concentration) , AGEs + CCP(25 μg/mL) , AGEs + CCP (50 μg/mL) and AGEs + CCP ( 100 μg/mL) , The proliferation of HUVECs was determined by the method of MTT, Real Time Quantitative Fluorescence RCR was used to analyze the expression of RAGE rnRNA and Western Blot was used to detect the expression of RAGE, The proliferation of HUVECs was increased after treatment with AGEs for 48 h, CCP significantly inhibited the pro-proliferation of HUVECs induced by AGEs in dose-dependent manner. The results of PCR and Western Blot also demonstrated that CCP could decrease the expression of RAGE mRNA and protein. CCP inhibited the activation of HUVECs induced by AGEs through inhibiting the expression of RAGE.%考察黄连多糖对高级糖基化终产物(AGEs)诱导人脐静脉内皮细胞(HUVECs)增殖和AGEs受体(RAGE)表达的作用.采用水提,Sevag法去蛋白,醇沉法获得黄连多糖(CCP);80%汇聚的HUVECs分成6组,分别为空白对照组、BSA对照组(蛋白浓度200μg/mL)、AGEs组(蛋白浓度200μg/mL)、AGEs+ CCP(25μg/mL)、AGEs+ CCP(50 μg/mL)和AGEs+ CCP(100μg/mL),采用MTT法检测黄连多糖对AGEs诱导HUVECs增殖的影响;实时荧光定量PCR检测RAGE mRNA表达;Westem Blot分析RAGE蛋白表达情况.HUVECs经AGEs诱导48h后,其增殖率显著增殖.黄连多糖可以剂量依赖性的抑制AGEs诱导HUVECs早期增殖作用,定量PCR和Western Blot结果表明CCP可以在mRNA和蛋白水平抑制RAGE表达.黄连多糖可通过抑制RAGE表达,降低AGEs对内皮细胞的激活作用.

  1. Lipoprotein Modification by Advanced Glycosylation Endproducts (AGEs): Role in Atherosclerosis.

    Science.gov (United States)

    Bucala, R

    1997-02-01

    Recent progress in our understanding of advanced glycosylation reactions in vivo has affirmed the hypothesis that these products play an important role in the evolution of both diabetic and nondiabetic vascular disease. Utilizing newly developed advanced glycosylation end-products (AGE)-specific enzyme-linked immunosorbent assay (ELISA) techniques, AGEs have been identified to be present on a variety of vascular wall, lipoprotein, and lipid constituents. Vascular wall AGEs contribute to vascular pathology by increasing vascular permeability, enhancing subintimal protein and lipoprotein deposition, and inactivating nitric oxide. Lipid-linked AGEs present in low-density lipoprotein (LDL) also have been shown to initiate oxidative modification, promoting oxidation reactions that may proceed without the involvement of free metals or other radical generating systems. AGE-specific ELISA analysis has demonstrated a significantly increased level of AGE-modified LDL in the plasma of diabetic patients when compared to normal controls. AGE-modification impairs LDL-receptor-mediated clearance mechanisms in vivo and may contribute to elevated LDL levels in patients with diabetes. This concept has been substantiated further by the recent clinical observations that administration of the advanced glycosylation inhibitor aminoguanidine to diabetic patients significantly decreases circulating LDL levels. (Trends Cardiovasc Med 1997;7:39-47). © 1997, Elsevier Science Inc.

  2. 糖基化终产物对脉络膜微血管内皮细胞增生和管腔形成的影响%Advanced glycation endproducts enhance proliferation, but not tube formation in choroidal microvascular endothelial cells

    Institute of Scientific and Technical Information of China (English)

    王雨生; Ulrike Friedrichs; Wolfram Eichler; Stephan Hoffmann; Peter Wiedemann

    2005-01-01

    ● AIM: To investigate the role of advanced glycation endproducts (AGEs) in the pathogenesis of age-related macular degeneration (AMD).● METHODS: Bovine choroidal endothelial cells (CEC:)were isolated by the modified protocol using lycopersicon esculentum agglutinin coated Dynabeads, and identiffed by immunocytochemical staining with anti-Factor Ⅷ antibody and uptaking of dil-acetylated low-density lipoprotein (dil-ac-LDL). AGEs were prepared by incubating 50g/L bovine serum albumin and 150g/L glucose at 37℃ for 6wk, which were characterized by dot blot assay with anti-AGEs antibody. CEC proliferation was evaluated using 3,(4,5-dimethylthiazol-2-yl)-2,5- diphenyl tetrazolium bromide (MTT) assay, and tube formation in CEC was determined by a Vitrogen system.● RESULTS: More than 90% of the cultured cells were positive to Factor V immunostaining and had the ability to uptake dil-ac-LDL, which were the features of endothelial cells. AGEs we prepared were affinitive to anti-AGEs antibody. After treatment with AGEs for a time course of 3d, CEC proliferation was significantly increased in a dose-dependent manner by AGEs at concentrations between 62.5 and 500mg/L. The cytokine,basic fibroblast growth factor (bFGF), enhanced strongly tube-like structure formation in CEC to 124% (P<0.05)above that of untreated controls. In this condition, AGEs at the concentrations of 500 and 50mg/L showed no effect on CEC tube formation (P>0.05).● CONCLUSION: The present study demonstrated that CEC proliferation was increased by AGEs, however, regarding there was no statistically effect on CEC tube formation. These findings confirm and extend that AGEs could be a potential initiator in the pathogenesis of choroidal neovascularization in exudative AMD, at least in part, through enhancement of CEC proliferation.%目的:研究糖基化终产物(advanced glycationendproducts,AGEs)在年龄相关性黄斑变性发生中的作用.方法:使用lycopersicon esculentum agglutinin包

  3. COPD纤维支气管镜肺泡灌洗液中可溶性晚期糖基化终末产物受体水平的临床意义%The Clinical Significances of Soluble Receptor for Advanced Glycation Endproducts in Bronchoscopy Alveolus Lavage Fluid among Patients with COPD

    Institute of Scientific and Technical Information of China (English)

    杨兴官; 雷超; 胡占升

    2014-01-01

    Objective To discuss the clinical significances of soluble receptor for advanced glycation end-products ( sRAGE)in bronchoscopy alveolus lavage fluid( BALF)in patients with COPD. Methods A total of 40 patients with COPD who were admitted to the department of intensive care unit of the First Hospital Affiliated to Liaoning Medical University from Oc-tober 2012 to May 2013,were selected as the COPD group,meanwhile 40 patients with non-COPD were selected as the non-COPD group,and these COPD patients were divided into mild group(12 cases),moderate group(10 cases),severe group (10 cases),very severe group(8 cases). The sRAGE concentrations in BALF were detected by enzyme-linked immunosor-bent assay(ELISA). Results The concentration of sRAGE in BALF of patients in the COPD group(191 ±71)ng/L was sig-nificantly higher than that in the non-COPD group(55 ±56)ng/L(t=9. 44,P<0. 001). The concentration of sRAGE in BALF of COPD patients in the mild group,moderate group,severe group and very severe group was(111 ± 44) ng/L,(184 ±45)ng/L,(226 ±34)ng/L,and(273 ±30)ng/L,respectively,there were significant differences in concentration of sRAGE among these groups(F=30. 48,P<0. 001),and the concentration of sRAGE in very severe COPD group was signifi-cantly higher than that in severe COPD group,the concentration of sRAGE in severe COPD group was significantly higher than that in moderate group,the concentration of sRAGE in moderate group was significantly higher than that in mild group( P <0. 05 ) . Linear correlation analysis results showed that the concentration of sRAGE in BALF of COPD patients were negatively cor-related with FEV1%(r= -0. 738,P <0. 05). Conclusion The concentration of sRAGE in BALF of COPD patients was higher than that of non-COPD patients;The concentration of sRAGE in BALF is related to severity of COPD,it could be used as an index of the prognosis evaluation of COPD.%目的:探讨纤维支气管镜肺泡灌洗液中可溶性晚期

  4. Advanced glycation end product ligands for the receptor for advanced glycation end products: Biochemical characterization and formation kinetics

    NARCIS (Netherlands)

    Valencia, J.V.; Weldon, S.C.; Quinn, D.; Kiers, G.H.; Groot, J. de; TeKoppele, J.M.; Hughes, T.E.

    2004-01-01

    Advanced glycation end products (AGEs) accumulate with age and at an accelerated rate in diabetes. AGEs bind cell-surface receptors including the receptor for advanced glycation end products (RAGE). The dependence of RAGE binding on specific biochemical characteristics of AGEs is currently unknown.

  5. Comprehensive identification of glycated peptides and their glycation motifs in plasma and erythrocytes of control and diabetic subjects.

    Science.gov (United States)

    Zhang, Qibin; Monroe, Matthew E; Schepmoes, Athena A; Clauss, Therese R W; Gritsenko, Marina A; Meng, Da; Petyuk, Vladislav A; Smith, Richard D; Metz, Thomas O

    2011-07-01

    Nonenzymatic glycation of proteins sets the stage for formation of advanced glycation end-products and development of chronic complications of diabetes. In this report, we extended our previous methods on proteomics analysis of glycated proteins to comprehensively identify glycated proteins in control and diabetic human plasma and erythrocytes. Using immunodepletion, enrichment, and fractionation strategies, we identified 7749 unique glycated peptides, corresponding to 3742 unique glycated proteins. Semiquantitative comparisons showed that glycation levels of a number of proteins were significantly increased in diabetes and that erythrocyte proteins were more extensively glycated than plasma proteins. A glycation motif analysis revealed that some amino acids were favored more than others in the protein primary structures in the vicinity of the glycation sites in both sample types. The glycated peptides and corresponding proteins reported here provide a foundation for potential identification of novel markers for diabetes, hyperglycemia, and diabetic complications in future studies.

  6. 姜黄素对2型糖尿病神经痛大鼠脊髓背角和背根神经节RAGE表达的影响%Effects of curcumin on expression of receptor for advanced glycation end-products in spinal dorsal horn and dorsal root ganglion of rats with type 2 diabetic neuropathic pain

    Institute of Scientific and Technical Information of China (English)

    史小婷; 徐霞; 曹红; 李佳佳; 吴绍胜; 李军

    2014-01-01

    Objective To evaluate the effects of curcumin on the expression of receptor for advanced glycation end-products (RAGE) in the spinal dorsal horn and dorsal root ganglion (DRG) of the rats with type 2 diabetic neuropathic pain (DNP).Methods Male Sprague-Dawley rats,weighing 160-180 g,were used in this study.Type 2 diabetes mellitus was induced by high-fat and high-sucrose diet for 8 weeks and intraperitoneal streptozotocin (STZ) 35 mg/kg and confirmed by fasting blood glucose level ≥ 16.7 mmol/L 3 days later.Type 2 DNPwas confirmed by the mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) measured on day 14 after STZ administration less than 80% of the baseline value.Eighty-one rats with type 2 DNP were randomly divided into 3 groups (n =27 each) using a random number table:DNP group,DNP + curcumin group (DCur group),and DNP+ solvent group (group DSC).In DCur and DSC groups,curcumin 100 mg· kg-1 · d-1 and corn oil 4 ml · kg-1 · d-1 were injected intraperitonally,respectively,for 14 consecutive days starting from the day 14 after STZ administration.Another 27 normal male Sprague-Dawley rats served as control group (group C) and were fed with normal forage.MWT and TWL were measured before STZ injection,at day 14 after STZ injection,and on 3,7 and 14 days after curcumin injection.RAGE positive cells were determined by immuno-histochemistry and the expression of RAGE by Western blot in the spinal dorsal horn and DRG after MWT and TWL were measured on 3,7 and 14 days after curcumin injection.Results Compared with group C,MWT was significantly decreased and TWL was shortened at 14 days after STZ injection and each time point after curcumin injection,the rate of RAGE positive cells in the spinal dorsal horn and DRG was increased at each time point after curcumin injection,and the expression of RAGE was up-regulated in the spinal dorsal horn at each time point after curcumin injection and in the DRG at 7 and 14 days after curcumin

  7. Efectos de los productos de glicación avanzada (AGEs y alendronato sobre el desarrollo osteoclástico: posibles mecanismos de acción Effect of Advanced Glycation Endproducts and Alendronate on osteoclastic development: possible mechanisms of action

    Directory of Open Access Journals (Sweden)

    María Virginia Gangoiti

    2012-03-01

    alendronato (10-5M no modificaron la expresión del RAGE en los cocultivos incubados con BSA (95 % respecto de BSA. Por otro lado, bajas dosis de alendronato en presencia de AGEs no alteraron la "up-regulation" del RAGE inducida por los AGEs (145 % respecto de BSA. Sin embargo, cuando los Oc se incubaron con AGEs y Ale 10-5M, esta dosis del bifosfonato bloqueá el efecto estimulante de los AGEs sobre la expresión de RAGE (105 % respecto de BSA. La incubación con 100 µg/ml AGE produjo una inhibición (50 % respecto de BSA, en la expresión del RANKL en los osteoblastos. El alendronato (10-8M-10-5M indujo también una inhibición del RANKL en forma dosis dependiente (65-47 % respecto de BSA. Por otro lado en presencia de AGEs, el alendronato (10-8M-10-5M no modificá la inhibición de la expresión del RANKL inducida por los AGEs (59-45 % del BSA. Conclusiones: Los AGEs y el alendronato inhiben el número y diferenciación de Oc en cultivo, con un efecto aditivo entre ambos a altas concentraciones de alendronato. También reducen la expresión de RANKL en osteoblastos, lo cual podría explicar parcialmente sus efectos sobre el reclutamiento y la maduración de Oc. Los AGEs y bajas dosis de alendronato aumentan la expresión de RAGE en Oc.Introduction: Patients with Diabetes mellitus frequently show osteopenia and/or osteoporosis, as well as an increase in low-trauma fracture risk. This has been postulated to be caused partially by the accumulation of advanced glycation endproducts (AGEs in bone extracellular matrix. AGEs could affect the homeostasis of bone cells, such as osteoblasts, osteocytes and osteoclasts. Osteoclasts (Oc are multi-nucleated cells specialized in resorbing bone. Bisphosphonates (BP are drugs widely used for treatment of bone diseases, and their principal mechanism of action is to inhibit the resorptive action of Oc. However, the use of BP for the treatment of patients with Diabetes-related bone disease is still controversial. Objective: To study the

  8. Autofluorescence characterization of advanced glycation end products of hemoglobin.

    Science.gov (United States)

    Vigneshwaran, Nadanathangam; Bijukumar, Gopalakrishnapillai; Karmakar, Nivedita; Anand, Sneh; Misra, Anoop

    2005-01-01

    This article describes the analysis of autofluorescence of advanced glycation end products of hemoglobin (Hb-AGE). Formed as a result of slow, spontaneous and non-enzymatic glycation reactions, Hb-AGE possesses a characteristic autofluorescence at 308/345 nm (lambda(ex)/lambda(em)). Even in the presence of heme as a quenching molecule, the surface presence of the glycated adduct gave rise to autofluorescence with the quantum yield of 0.19. The specificity of monoclonal antibody developed against common AGE structure with Hb-AGE was demonstrated using reduction in fluorescence polarization value due to increased molecular volume while binding. The formation of fluorescent adduct in hemoglobin in the advanced stage of glycation and the non-fluorescent HbA(1c) will be of major use in distinguishing and to know the past status of diabetes mellitus. While autofluorescence correlated highly with HbA(1c) value under in vivo condition (r = 0.85), it was moderate in the clinical samples (r = 0.55). The results suggest a non-linear relation between glycemia and glycation, indicating the application of Hb-AGE as a measure of susceptibility to glycation rather than glycation itself.

  9. Targeting advanced glycation with pharmaceutical agents: where are we now?

    Science.gov (United States)

    Borg, Danielle J; Forbes, Josephine M

    2016-08-01

    Advanced glycation end products (AGEs) are the final products of the Maillard reaction, a complex process that has been studied by food chemists for a century. Over the past 30 years, the biological significance of advanced glycation has also been discovered. There is mounting evidence that advanced glycation plays a homeostatic role within the body and that food-related Maillard products, intermediates such as reactive α-dicarbonyl compounds and AGEs, may influence this process. It remains to be understood, at what point AGEs and their intermediates become pathogenic and contribute to the pathogenesis of chronic diseases that inflict current society. Diabetes and its complications have been a major focus of AGE biology due to the abundance of excess sugar and α-dicarbonyls in this family of diseases. While further temporal information is required, a number of pharmacological agents that inhibit components of the advanced glycation pathway have already showed promising results in preclinical models. These therapies appear to have a wide range of mechanistic actions to reduce AGE load. Some of these agents including Alagebrium, have translated successfully to clinical trials, while others such as aminoguanidine, have had undesirable side-effect profiles. This review will discuss different pharmacological agents that have been used to reduce AGE burden in preclinical models of disease with a focus on diabetes and its complications, compare outcomes of those therapies that have reached clinical trials, and provide further rationale for the use of inhibitors of the glycation pathway in chronic diseases.

  10. Collagen advanced glycation inhibits its Discoidin Domain Receptor 2 (DDR2)-mediated induction of lysyl oxidase in osteoblasts.

    Science.gov (United States)

    Khosravi, Roozbeh; Sodek, Katharine L; Faibish, Michael; Trackman, Philip C

    2014-01-01

    Diabetes increases the risk of bone fracture. Organic and inorganic bone extracellular matrix components determine bone strength. Previous studies indicate that in diabetes, glycation of collagen causes abnormal arrangements of collagen molecules and fragile bones. Diabetic bone fragility is additionally attributed to reduced levels of lysyl oxidase enzyme-dependent collagen cross-links. The mechanism underlying the presence of lower enzymatic collagen cross-links in diabetic bone has not been directly investigated. Here we determine in primary osteoblast cultures the regulation of lysyl oxidase protein by type I collagen and collagen modified by carboxymethylation (CML-collagen), a form of advanced glycation endproducts. Data indicate that non-glycated collagen up-regulates lysyl oxidase levels both in primary non-differentiated and in differentiating mouse and rat osteoblast cultures, while CML-collagen fails to regulate lysyl oxidase in these cells. Collagen binding to Discoidin Domain Receptor-2 (DDR2) mediates lysyl oxidase increases, determined in DDR2 shRNA knockdown studies. DDR2 binding and activation were disrupted by collagen glycation, pointing to a mechanism for the diminished levels of lysyl oxidase and consequently low lysyl oxidase-derived cross-links in diabetic bone. Our studies indicate that collagen-integrin interactions may not play a major role in up-regulating lysyl oxidase. Furthermore, non-collagenous ligands for the receptor for advanced glycation end products (RAGE) failed to alter lysyl oxidase levels. Taken together with published studies a new understanding emerges in which diabetes- and age-dependent inhibition of normal collagen-stimulated DDR2- and integrin-signaling, and independent advanced glycation-stimulated RAGE-signaling, each contributes to different aspects of diabetic osteopenia.

  11. Receptor for Advanced Glycation End Products and its Inflammatory Ligands are Upregulated in Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Judyta eJuranek

    2015-12-01

    Full Text Available Amyotrophic lateral sclerosis (ALS is a fatal motor neuron disorder of largely unknown pathogenesis. Recent studies suggest that enhanced oxidative stress and neuroinflammation contribute to the progression of the disease. Mounting evidence implicates the receptor for advanced glycation end-products (RAGE as a significant contributor to the pathogenesis of certain neurodegenerative diseases and chronic conditions. It is hypothesized that detrimental actions of RAGE are triggered upon binding to its ligands, such as AGEs (advanced glycation end products, S100/calgranulin family members, and High Mobility Group Box-1 (HMGB1 proteins. Here, we examined the expression of RAGE and its ligands in human ALS spinal cord. Tissue samples from age-matched human control and ALS spinal cords were tested for the expression of RAGE, carboxymethyllysine (CML AGE, S100B and HMGB1, and intensity of the immunofluorescent and immunoblotting signals was assessed. We found that the expression of both RAGE and its ligands was significantly increased in the spinal cords of ALS patients versus age-matched control subjects. Our study is the first report describing co-expression of both RAGE and its ligands in human ALS spinal cords. These findings suggest that further probing of RAGE as a mechanism of neurodegeneration in human ALS is rational.

  12. Effects of advanced glycation end-products on the expression of parathyroid hormone related peptide and vascular calcification on vascular smooth muscle cells%糖基化终产物对人血管平滑肌细胞表达及分泌甲状旁腺激素相关肽和血管钙化的影响

    Institute of Scientific and Technical Information of China (English)

    张琴; 刘乃丰

    2014-01-01

    Objective:To investigate the effects of advanced glycation end-products(AGEs) on expression and secretion of parathyroid hormone related peptide(PTHrP)in vitro cultured human vascular smooth muscle cells (HVSMCs), and explore the related mechanism of PTHrP influencing vascular smooth muscle cells calcification . Methods:HVSMCs were treated with AGE-BSA of indicated concentration or non-glycated BSA for same periods . The calcium contents and activity of alkaline phosphatase of cells were analyzed by microplate reader ;PTHrP levels in the supernatant were detected by the enzyme-linked immunosorbent method .Real-time fluorescent quantitative reverse transcription polymerase chain reaction ( RT-PCR) was performed to detect the expressive of PTHrP , core- binding factor α1(cbfα1) in human and bone morphogenetic protein-2(BMP-2) in vascular smooth muscle cells . Results:AGE-BSA increased calcium deposition and activity of alkaline phosphatase in HVSMCs in dose-independent manners( P<0.05) , but reduced the secretion of PTHrP.Futhermore, the elevated AGE-BSA treatment on HVSMCs significantly enhanced the expression of cbfα1, BMP-2 and PTHrP, compared with the controls( P <0.05 ) .Conclusion: The expression and secretion of PTHrP on human vascular smooth muscle cells can be effected by AGEs , and PTHrP may induce deposition of calcium on vascular smooth muscle cells, thereby contributing to the vascular calcification .However, the related mechanism will be further explored .%目的:观察糖基化终末产物(AGEs)对人血管平滑肌细胞表达及分泌甲状旁腺激素相关肽(PTHrP)功能的影响,探讨PTHrP影响血管平滑肌细胞钙化发生的相关机制。方法:不同浓度的AGE-BSA分别与人血管平滑肌细胞孵育相同时间后,检测各组细胞钙含量及碱性磷酸酶( ALP)活性判断钙化程度;酶联免疫吸附法检测各组细胞PTHrP的分泌量;实时荧光定量逆转录聚合酶链反应检

  13. Advanced glycation end products in renal failure: an overview.

    Science.gov (United States)

    Noordzij, M J; Lefrandt, J D; Smit, A J

    2008-12-01

    The article aims to present an overview of the existing knowledge on advanced glycation end products (AGE). They are moieties that bind to proteins, but also lipids and nuclear acids. AGE are formed during glycation and oxidative stress. Accumulation of AGE occurs especially in diabetes and chronic renal failure and plays a major pathogenetic role. The deleterious effects of AGE result from cross-linking of proteins and activation of the receptor for advanced glycation end products. AGE accumulation can be noninvasively assessed by the skin autofluorescence reader. In diabetics, the skin autofluorescence predicts cardiac mortality and the occurrence of macro- and microvascular complications. In patients on haemodialysis, skin autofluorescence is highly elevated and predicts mortality. After renal transplantation AGE accumulation is lower than during haemodialysis, but still remains elevated and is a strong risk factor for chronic renal transplant dysfunction. Some of the potential methods to intervene with AGE accumulation are discussed in this article.

  14. Targeted reduction of advanced glycation improves renal function in obesity

    DEFF Research Database (Denmark)

    Harcourt, Brooke E; Sourris, Karly C; Coughlan, Melinda T

    2011-01-01

    function and an inflammatory profile (monocyte chemoattractant protein-1 (MCP-1) and macrophage migration inhibitory factor (MIF)) were improved following the low-AGE diet. Mechanisms of advanced glycation-related renal damage were investigated in a mouse model of obesity using the AGE...

  15. Breakers of advanced glycation end products restore large artery properties in experimental diabetes

    NARCIS (Netherlands)

    Wolffenbuttel, B H; Boulanger, C M; Crijns, F R; Huijberts, M S; Poitevin, P; Swennen, G N; Vasan, S; Egan, J J; Ulrich, P; Cerami, A; Lévy, B I

    1998-01-01

    Glucose and other reducing sugars react with proteins by a nonenzymatic, posttranslational modification process called nonenzymatic glycation. The formation of advanced glycation end products (AGEs) on connective tissue and matrix components accounts largely for the increase in collagen crosslinking

  16. Metalloproteinases and advanced glycation end products: coupled navigation in atherosclerotic plaque pathophysiology?

    Science.gov (United States)

    Furfaro, A L; Sanguineti, R; Storace, D; Monacelli, F; Puzzo, A; Pronzato, M A; Odetti, P; Traverso, N

    2012-11-01

    Matrix metalloproteinases (MMPs), their inhibitors (TIMPs) and inflammatory cytokines, such as interleukin-1 (IL-1), are considered markers of evolution and/or instability of atherosclerotic plaques. Accumulation of Advanced Glycation Endproducts (AGE) is a well known phenomenon in diabetes and has also been considered in the pathogenesis of atherosclerosis. Aim of the present study was to analyse the levels of pentosidine, a fluorescent AGE, and to evaluate the expression of MMP-2, TIMP-3, and IL-1 in an ex vivo model of human advanced atherosclerotic plaques. We intended to test the possible correlation between pentosidine and markers of ECM remodelling and inflammation in the atherosclerotic process, and to investigate if classic risk factors, such as diabetes and hypertension, influenced these biochemical parameters. We found that diabetic plaques showed higher level of pentosidine, as expected, but much lower, or even undetectable, expression levels of MMP-2 and TIMP-3; IL-1 expression was not different between diabetic and non diabetic plaques. Hypertension did not influence any of these parameters. Although the statistical correlations between the expression of the considered genes and pentosidine did not reach significance, slight negative trends were noted between TIMP-3 and IL-1 expression vs. pentosidine content. We suggest that in mature diabetic plaques AGE accumulation can exert stabilizing effects on matrix proteins, while scanty cell presence leads to poor capacity of reactive responses, such as remodelling and inflammation.

  17. Surveying the Effect of Hydroalcoholic Extract of Allium hirtifolium on Glycated Hemoglobin Formation in In-vitro Condition

    OpenAIRE

    Shirin Fattahpour; Farzaneh Hosseini; Mohammad Reza Hajizadeh; Mohammad Asadpour; gholam hossein hassanshahi; mohammad reza mirzaii; Mehdi Mahmoodi

    2015-01-01

    Background & Objectives: Non enzymatic glycation is a reaction that occurs between reducing sugars and amino groups of proteins. Advanced Glycation End-products (AGE) have been accounted for principal biological processes like aging and pathogenesis of some diseases. Accumulation of AGE during hyperglycemia can cause structural and functional changes of long-lived proteins. Therefore, it will be effective to inhibit protein glycation formation in order to reduce or to ...

  18. Inhibition of nonenzymatic protein glycation by pomegranate and other fruit juices.

    Science.gov (United States)

    Dorsey, Pamela Garner; Greenspan, Phillip

    2014-04-01

    The nonenzymatic glycation of proteins and the formation of advanced glycation endproducts in diabetes leads to the crosslinking of proteins and disease complications. Our study sought to demonstrate the effect of commonly consumed juices (pomegranate, cranberry, black cherry, pineapple, apple, and Concord grape) on the fructose-mediated glycation of albumin. Albumin glycation decreased by 98% in the presence of 10 μL of pomegranate juice/mL; other juices inhibited glycation by only 20%. Pomegranate juice produced the greatest inhibition on protein glycation when incubated at both the same phenolic concentration and the same antioxidant potential. Both punicalagin and ellagic acid significantly inhibited the glycation of albumin by ~90% at 5 μg/mL. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that pomegranate, but not apple juice, protected albumin from modification. These results demonstrate that pomegranate juice and two of its major constituents are potent inhibitors of fructose-mediated protein glycation.

  19. Mass spectrometric determination of early and advanced glycation in biology.

    Science.gov (United States)

    Rabbani, Naila; Ashour, Amal; Thornalley, Paul J

    2016-08-01

    Protein glycation in biological systems occurs predominantly on lysine, arginine and N-terminal residues of proteins. Major quantitative glycation adducts are found at mean extents of modification of 1-5 mol percent of proteins. These are glucose-derived fructosamine on lysine and N-terminal residues of proteins, methylglyoxal-derived hydroimidazolone on arginine residues and N(ε)-carboxymethyl-lysine residues mainly formed by the oxidative degradation of fructosamine. Total glycation adducts of different types are quantified by stable isotopic dilution analysis liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Metabolism of glycated proteins is followed by LC-MS/MS of glycation free adducts as minor components of the amino acid metabolome. Glycated proteins and sites of modification within them - amino acid residues modified by the glycating agent moiety - are identified and quantified by label-free and stable isotope labelling with amino acids in cell culture (SILAC) high resolution mass spectrometry. Sites of glycation by glucose and methylglyoxal in selected proteins are listed. Key issues in applying proteomics techniques to analysis of glycated proteins are: (i) avoiding compromise of analysis by formation, loss and relocation of glycation adducts in pre-analytic processing; (ii) specificity of immunoaffinity enrichment procedures, (iii) maximizing protein sequence coverage in mass spectrometric analysis for detection of glycation sites, and (iv) development of bioinformatics tools for prediction of protein glycation sites. Protein glycation studies have important applications in biology, ageing and translational medicine - particularly on studies of obesity, diabetes, cardiovascular disease, renal failure, neurological disorders and cancer. Mass spectrometric analysis of glycated proteins has yet to find widespread use clinically. Future use in health screening, disease diagnosis and therapeutic monitoring, and

  20. Advanced glycation end-products and skin autofluorescence in end-stage renal disease : a review

    NARCIS (Netherlands)

    Arsov, Stefan; Graaff, Reindert; van Oeveren, Wim; Stegmayr, Bernd; Sikole, Aleksandar; Rakhorst, Gerhard; Smit, Andries J.

    2014-01-01

    Chronic kidney disease (CKD), especially in its end stage, is marked by extremely high cardiovascular rates of morbidity and mortality; hemodialysis patients have a five-fold shorter life expectancy than healthy subjects of the same age. In CKD the metabolic products that accumulate in the body are

  1. The association between glyceraldehyde-derived advanced glycation end-products and colorectal cancer risk

    NARCIS (Netherlands)

    Kong, So Yeon; Takeuchi, Masayoshi; Hyogo, Hideyuki; McKeown-Eyssen, Gail; Yamagishi, Sho Ichi; Chayama, Kazuaki; O'Brien, Peter J.; Ferrari, Pietro; Overvad, Kim; Olsen, Anja; Tjønneland, Anne; Boutron-Ruault, Marie Christine; Bastide, Nadia; Carbonnel, Franck; Kühn, Tilman; Kaaks, Rudolf; Boeing, Heiner; Aleksandrova, Krasimira; Trichopoulou, Antonia; Lagiou, Pagona; Vasilopoulou, Effie; Masala, Giovanna; Pala, Valeria; De Magistris, Maria Santucci; Tumino, Rosario; Naccarati, Alessio; Bueno-De-Mesquita, H. B.; Peeters, Petra H.; Weiderpass, Elisabete; Quiŕos, J. Ramón; Jakszyn, Paula; ͆anchez, María Jos̈e; Dorronsoro, Miren; Gavrila, Diana; Ardanaz, Eva; Rutegård, Martin; Nyström, Hanna; Wareham, Nicholas J.; Khaw, Kay Tee; Bradbury, Kathryn E.; Romieu, Isabelle; Freisling, Heinz; Stavropoulou, Faidra; Gunter, Marc J.; Cross, Amanda J.; Riboli, Elio; Jenab, Mazda; Bruce, W. Robert

    2015-01-01

    Background: A large proportion of colorectal cancers are thought to be associated with unhealthy dietary and lifestyle exposures, particularly energy excess, obesity, hyperinsulinemia, and hyperglycemia. It has been suggested that these processes stimulate the production of toxic reactive carbonyls

  2. Skin Autofluorescence as Marker of Tissue Advanced Glycation End-Products Accumulation in Formerly Preeclamptic Women

    NARCIS (Netherlands)

    Coffeng, S.M.; Blaauw, Judith; Souwer, E.T.; Rakhorst, G.; Smit, A.J.; Graaff, R.; van Doormaal, J.J.; Aarnoudse, J.G.; Faas, M.M.; van Pampus, Maria

    2011-01-01

    Condensation. In women with a history of preeclampsia skin autofluorescence as marker of tissue AGEs accumulation is increased, supporting a common causal metabolic or vascular link between preeclampsia and cardiovascular diseases. Objective. To investigate whether skin autofluorescence (AF), as mar

  3. Advanced glycation endproducts and their receptor in different body compartments in COPD

    NARCIS (Netherlands)

    Hoonhorst, Susan J M; Lo Tam Loi, Adèle T; Pouwels, Simon D; Faiz, Alen; Telenga, Eef D; van den Berge, Maarten; Koenderman, L; Lammers, Jan-Willem J; Boezen, H Marike; van Oosterhout, Antoon J M; Lodewijk, Monique E; Timens, Wim; Postma, Dirkje S; Ten Hacken, Nick H T

    2016-01-01

    BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a chronic lung disease characterized by chronic airway inflammation and emphysema, and is caused by exposure to noxious particles or gases, e.g. cigarette smoke. Smoking and oxidative stress lead to accelerated formation and accumulation of

  4. Reduction of serum advanced glycation end-products with a low calorie Mediterranean diet.

    Science.gov (United States)

    Rodríguez, Juan Manuel; Leiva Balich, Laura; Concha, M J; Mizón, C; Bunout Barnett, Daniel; Barrera Acevedo, Gladys; Hirsch Birn, Sandra; Jiménez Jaime, Teresa; Henríquez, Sandra; Uribarri, Jaime; de la Maza Cave, María Pía

    2015-06-01

    La ingesta dietaria de productos finales de glicación avanzada (AGEs) aumenta los niveles séricos y tisulares de estas sustancias, lo que contribuye a un estado de mayor estrés oxidativo e inflamación. Una intervención dietaria con bajo contenido de AGEs ha demostrado reducir el contenido de AGEs en el cuerpo. La dieta mediterránea (DM) se considera teóricamente baja en AGEs, pero los efectos específicos de este tipo de intervención en los niveles séricos de AGEs no ha sido probado. Metodología: cuarenta y siete mujeres premenopáusicas con sobrepeso u obesidad se sometieron a tres meses de restricción calórica (20 kcal por kg de peso corporal inicial) con una dieta de tipo mediterráneo que excluía la ingesta de vino. La adherencia a la DM se evaluó al comienzo y al final del tratamiento utilizando una encuesta on-line, con puntuaciones de 0 a 14 (mínima a máxima adherencia a la DM). La composición corporal, la resistencia a la insulina, los niveles séricos de lipoproteínas y carboximetil-lisina (CML) se midieron en ambos períodos. El CML sérico se evaluó mediante ELISA (ensayo inmunoenzimático). La adherencia a la restricción calórica se evaluó de acuerdo con la pérdida de peso ( 5% del peso inicial). Resultados: la media de peso corporal, grasa corporal, circunferencia de la cintura, colesterol total, triglicéridos y CML sérica disminuyeron significativamente, junto con un aumento en el puntaje de adherencia a la DM, aunque ninguno de los pacientes alcanzó la máxima puntuación. Hubo cambios significativos en los niveles de CML y de resistencia a la insulina en 17 mujeres clasificadas como adherentes a la restricción calórica, pero no en las 27 participantes que fueron consideradas adherentes a la DM (de acuerdo con la mejoría en el puntaje de la encuesta). Conclusiones: los niveles séricos de CML disminuyeron tras la restricción calórica con una dieta tipo mediterránea. Dado que no se pudo alcanzar la puntuación máxima en la encuesta de DM, no podemos concluir si la propia DM tiene un efecto aditivo a la restricción calórica.

  5. Reactive immunization suppresses advanced glycation and mitigates diabetic nephropathy.

    Science.gov (United States)

    Shcheglova, Tatiana; Makker, Sudesh; Tramontano, Alfonso

    2009-05-01

    Agents that inhibit glycation end products by reducing the carbonyl load from glycation and glycoxidation are an emerging pharmacologic approach to treat complications of diabetes. We previously demonstrated that antibodies generated to the glycoprotein keyhole limpet hemocyanin (KLH) can cross-link with reactive carbonyl residues on protein conjugates. Here, we immunized streptozotocin-induced diabetic rats with KLH to assess the capacity of the elicited antibodies to intercept carbonyl residues on glycated proteins and to mitigate glycation-related pathology. Compared with diabetic rats immunized with adjuvant alone, KLH-immunized diabetic rats had decreased levels of glycated peptides in sera and demonstrated a reduction in albuminuria, proteinuria, deposition of glycation end products in the kidney, and histologic damage. In vitro, low molecular weight glycated peptides from rat serum reacted with anti-KLH antibodies at a faster rate than normal IgG and selectively modified the lambda chains. The reaction products contained peptide sequences from type I collagen alpha chain, albumin, and LDL receptor-related protein. These adduction reactions were inhibited by free KLH and by reduction of glycated peptides with borohydride. In summary, these results suggest that inherent reactivity of Ig light chains provides a natural mechanism for the removal of cytotoxic glycation products. This reactivity can be augmented by glycoprotein-specific reactive immunization, a potential biopharmaceutical approach to glycation-related pathology.

  6. Accumulation of advanced glycation end products, measured as skin autofluorescence, in renal disease

    NARCIS (Netherlands)

    Hartog, JWL; De Vries, APJ; Lutgers, HL; Meerwaldt, R; Huisman, RM; Van Son, WJ; De Jong, PE; Smit, AJ; Baynes, JW; Monnier, VM; Ames, JM; Thorpe,

    2005-01-01

    Advanced glycation end products (AGEs) accumulate during renal failure and dialysis. Kidney transplantation is thought to reverse this accumulation by restoring renal function. Using a noninvasive and validated autofluorescence reader, we evaluated AGE levels in 285 transplant recipients (mean age,

  7. The Parkinsonism-associated protein DJ-1/Park7 prevents glycation damage in human keratinocyte.

    Science.gov (United States)

    Advedissian, Tamara; Deshayes, Frédérique; Poirier, Françoise; Viguier, Mireille; Richarme, Gilbert

    2016-04-22

    Reducing sugars and dicarbonyls form covalent adducts with proteins through a nonenzymatic process known as glycation, which inactivates proteins, is increased in diabetic patients and is associated with diabetic complications, including retinopathy, cataracts, nephropathy, neuropathy, cardiomyopathy and skin defects. We recently characterized DJ-1/Park7 as a protein deglycase that repairs proteins from glycation by glyoxal and methylglyoxal, two major glycating agents which are responsible for up to 65% of glycation events. In this study, we investigated the ability of DJ-1 to prevent protein glycation in keratinocytes. Glycation of collagen and keratinocyte proteins was tested by measuring ultraviolet absorption and fluorescence emission. Protein glycation in HaCaT keratinocytes was investigated by immunodetection with anti-advanced glycation endproduct antibodies, after DJ-1 depletion or overexpression. In vitro, DJ-1 prevented glycation of collagen and keratinocyte protein extracts. In cell culture, DJ-1 depletion by small interfering RNAs resulted in a 3-fold increase in protein glycation levels. Moreover, protein glycation levels were decreased several-fold in cells overexpressing DJ-1 after addition of the Nrf2 inducer sulforaphane or after transfection with a DJ-1 plasmid. Thus, the DJ-1 deglycase plays a major role in preventing protein glycation in eukaryotic cells and might be important for preventing skin glycation.

  8. Adverse effects of advanced glycation end products on embryonal development

    Directory of Open Access Journals (Sweden)

    Hiramatsu,Yuji

    2008-04-01

    Full Text Available We studied the effects of advanced glycation end products (AGEs, which are known to accumulate in patients with diabetes, autoimmune diseases, or those who smoke, on embryonal development. Pronuclear (PN embryos were obtained by flushing the fallopian tubes of rats after superovulation and mating. The cleavage rate and blastocyst yield were evaluated at 24, 72, 96, and 120 h of culture. Glyoxal, an AGE-forming aldehyde, suppressed embryonal development at every stage from PN to blastocyst in a concentration-dependent manner. The cleavage rate of the embryo was also signifi cantly decreased by treatment with glyoxal at concentrations of 1 mM or higher. The blastocyst yield was significantly decreased by treatment with glyoxal at concentrations of 0.5 mM or higher. N-acetyl-L-cysteine (L-NAC at 1 mM significantly suppressed the glyoxal-induced embryonal toxicity. BSA-AGEs at 5 microg/ml or higher concentration signifi cantly reduced the cleavage rate and blastocyst yield compared to those for BSA-treated embryos. L-NAC at 1 mM significantly suppressed BSAAGE-induced embryonal toxicity. Because AGEs are embryo-toxic, AGE contamination may influence the pregnancy rate of in vitro fertilization and embryo transfer. AGEs, which are increased in women under pathological conditions, may also be involved in their infertility.

  9. Advanced Glycation End Products Play Adverse Proinflammatory Activities in Osteoporosis

    Directory of Open Access Journals (Sweden)

    Roberta Sanguineti

    2014-01-01

    Full Text Available Osteoporosis is a major public health burden that is expected to further increase as the global population ages. In the last twenty years, advanced glycation end products (AGEs have been shown to be critical mediators both in the pathogenesis and development of osteoporosis and other chronic degenerative diseases related to aging. The accumulation of AGEs within the bone induces the formation of covalent cross-links with collagen and other bone proteins which affects the mechanical properties of tissue and disturbs bone remodelling and deterioration, underlying osteoporosis. On the other hand, the gradual deterioration of the immune system during aging (defined as immunosenescence is also characterized by the generation of a high level of oxidants and AGEs. The synthesis and accumulation of AGEs (both localized within the bone or in the systemic circulation might trigger a vicious circle (in which inflammation and aging merged in the word “Inflammaging” which can establish and sustain the development of osteoporosis. This narrative review will update the molecular mechanisms/pathways by which AGEs induce the functional and structural bone impairment typical of osteoporosis.

  10. Interaction of reactive oxygen species in atherogenetic properties of advanced glycation end products in diabetes%活性氧与糖基化终产物致动脉粥样硬化作用的关系

    Institute of Scientific and Technical Information of China (English)

    冯契; 刘乃丰

    2003-01-01

    There is overwhelming evidence for an involvement of reactive oxygen species(ROS) in the pathogenesis of atherosclerosis (AS) in diabetes mellitus (DM). For many years, knowledge on the contribution to diabetic complications and vascular disease induced by advanced glycation end-products (AGEs) has been rising. During the development of atherosclerosis, AGEs and ROS might have interaction. In this article, weprovided four angles of view to discuss the role of ROS in the pathogenesis of atherosclerosis: the chemistry of ROS, the effect of vascular targets of ROS on activity of AGEs, the role of ROS in the pathogenesis of atherogenesis by AGEs, the same effect of ROS and AGEs-transcriptional regulation.

  11. Preserving brain function in aging: The anti-glycative potential of berry fruit

    Science.gov (United States)

    Advanced glycation end-products (AGEs) are naturally occurring macromolecules that are formed in vivo by the non-enzymatic modification of proteins, lipids, or nucleic acids by sugar, even in the absence of hyperglycemia. In the diet, AGEs are found in animal products, and additional AGEs are produc...

  12. Inhibitory effect of leonurine on the formation of advanced glycation end products.

    Science.gov (United States)

    Huang, Lianqi; Yang, Xin; Peng, Anlin; Wang, Hui; Lei, Xiang; Zheng, Ling; Huang, Kun

    2015-02-01

    Long-term hyperglycemia is a typical symptom of diabetes mellitus (DM) which can cause a high level of protein glycation and lead to the formation of advanced glycation end products (AGEs). The accumulation of AGEs in turn deteriorates DM and its complications. Insulin, the only hormone that directly decreases blood sugar in vivo, is vulnerable to glycation which causes the loss of its biological activity. In this study, we used a porcine insulin (PI)-methylglyoxal (MGO) model to investigate the inhibitory effect of leonurine (LN), a natural alkaloid extracted from Herba leonuri, on AGE formation. Assays including AGE-specific fluorescence, and fructosamine level and carbonyl group content determination showed that LN can dose-dependently suppress PI glycation. A significantly decreased cross-linking level on the glycated PI was also proven by SDS-PAGE electrophoresis. A further liquid chromatography-mass spectrometry study suggested that LN may inhibit PI glycation through trapping MGO and keeping it from reacting with PI. Our results thus indicate that LN is a promising anti-glycation agent for the prevention of diabetes and its complications via inhibiting AGE formation.

  13. Possible participation of receptor for advanced glycation end products (RAGE) in the origin of cancer stem cells in diabetic patients with colon cancer.

    Science.gov (United States)

    Hu, Xiang; Cheng, Yong

    2013-05-01

    The association between diabetes and the associated increased risk of several solid malignancies has been the subject of investigation for many years, while potential biologic links between the two diseases are incompletely understood. The receptor for advanced glycation end-products (RAGE) signal transduction may represent a focal point in their respective contributions to malignant transformation associated diabetes. While the physiopathology of RAGE axis in promoting malignancies cannot be explained completely by the available mechanism as perpetuating inflammation at tumor microenvironment. In addition, experimental researches revealed a crucial role for upstreams of RAGE signaling pathway in maintaining the stemness properties and tumorigenicity of cancer stem cells. Hence, we hypothesized that RAGE inducing cancer stem cells may be a key determinant in the origin and progression of colon malignant tumors concomitant diabetes. Such an opinion not only bands together the seemingly disparate various complications in diabetes and colon cancers, but also has future implications for risk assessment and biopharmaceutical treatment.

  14. Determination of glycated hemoglobin in patients with advanced liver disease

    Institute of Scientific and Technical Information of China (English)

    Theresa Lahousen; Karin Hegenbarth; Rottraut Ille; Rainer W. Lipp; Robert Krause; Randie R. Little; Wolfgang J. Schnedl

    2004-01-01

    AIM: To evaluate the glycated hemoglobin (HbA1c)determination methods and to determine fructosamine in patients with chronic hepatitis, compensated cirrhosis and in patients with chronic hepatitis treated with ribavirin.METHODS: HbA1c values were determined in 15 patients with compensated liver cirrhosis and in 20 patients with chronic hepatitis using the ion-exchange high performance liquid chromatography and the immunoassay methods.Fructosamine was determined using nitroblue tetrazolium.RESULTS: Forty percent of patients with liver cirrhosis had HbA1c results below the non-diabetic reference range by at least one HbA1c method, while fructosamine results were either within the reference range or elevated. Twenty percent of patients with chronic hepatitis (hepatic fibrosis)had HbA1c results below the non-diabetic reference range by at least one HbA1c method. In patients with chronic hepatitis treated with ribavirin, 50% of HbA1c results were below the non-diabetic reference using at least one of the HbA1c methods.CONCLUSION: Only evaluated in context with all liver function parameters as well as a red blood count including reticulocytes, HbA1c results should be used in patients with advanced liver disease. HbA1c and fructosamine measurements should be used with caution when evaluating long-term glucose control in patients with hepatic cirrhosis or in patients with chronic hepatitis and ribavirin treatment.

  15. An Emerging Role of Glucagon-Like Peptide-1 in Preventing Advanced-Glycation-End-Product-Mediated Damages in Diabetes

    Directory of Open Access Journals (Sweden)

    Alessandra Puddu

    2013-01-01

    Full Text Available Glucagon-like peptide-1 (GLP-1 is a gut hormone produced in the intestinal epithelial endocrine L cells by differential processing of the proglucagon gene. Released in response to the nutrient ingestion, GLP-1 plays an important role in maintaining glucose homeostasis. GLP-1 has been shown to regulate blood glucose levels by stimulating glucose-dependent insulin secretion and inhibiting glucagon secretion, gastric emptying, and food intake. These antidiabetic activities highlight GLP-1 as a potential therapeutic molecule in the clinical management of type 2 diabetes, (a disease characterized by progressive decline of beta-cell function and mass, increased insulin resistance, and final hyperglycemia. Since chronic hyperglycemia contributed to the acceleration of the formation of Advanced Glycation End-Products (AGEs, a heterogeneous group of compounds derived from the nonenzymatic reaction of reducing sugars with free amino groups of proteins implicated in vascular diabetic complications, the administration of GLP-1 might directly counteract diabetes pathophysiological processes (such as pancreatic β-cell dysfunction. This paper outlines evidence on the protective role of GLP-1 in preventing the deleterious effects mediated by AGEs in type 2 diabetes.

  16. Plasma Levels of Soluble Receptor for Advanced Glycation End Products and Coronary Atherosclerosis: Possible Correlation with Clinical Presentation

    Directory of Open Access Journals (Sweden)

    Colomba Falcone

    2013-01-01

    Full Text Available Receptor for Advanced Glycation End-products (RAGE is a multi-ligand receptor ubiquitous present on epithelial, neuronal, vascular and inflammatory cells, usually expressed at low levels in homeostasis and to increased degrees at sites of stress or injury. The aim of the present study was to evaluate sRAGE plasma levels in patients with Acute Coronary Syndrome (ACS and to assess its diagnostic efficacy in identification of patients with acute events. Plasma levels of sRAGE were determined in 860 patients with Coronary Artery Disease (CAD: 530 patients presented stable angina and 330 were observed during acute ischemic event (147 with unstable angina and 183 with myocardial infarction. sRAGE plasma levels were significantly lower in patients with ACS than in patients with stable angina: [median 584 pg/mL (IQR: 266–851 pg/mL in MI patients, median 769 pg/mL (IQR: 394–987 pg/mL in patients with unstable angina, median 834 pg/mL (IQR 630–1005 pg/mL in patients with stable angina; P<0.001]. sRAGE levels did not differ among ACS patients stratified by the extent of coronary artery disease. In conclusion, this study confirm the role of sRAGE in activation and progression of inflammatory process and suggests the possibility that sRAGE can be considered an indicator of destabilization of vulnerable plaque.

  17. Involvement of Endoplasmic Reticulum Stress, Autophagy, and Apoptosis in Advanced Glycation End Products-Induced Glomerular Mesangial Cell Injury

    Science.gov (United States)

    Chiang, Chih-Kang; Wang, Ching-Chia; Lu, Tien-Fong; Huang, Kuo-How; Sheu, Meei-Ling; Liu, Shing-Hwa; Hung, Kuan-Yu

    2016-01-01

    Advanced glycation end-products (AGEs)-induced mesangial cell death is one of major causes of glomerulus dysfunction in diabetic nephropathy. Both endoplasmic reticulum (ER) stress and autophagy are adaptive responses in cells under environmental stress and participate in the renal diseases. The role of ER stress and autophagy in AGEs-induced mesangial cell death is still unclear. Here, we investigated the effect and mechanism of AGEs on glomerular mesangial cells. AGEs dose-dependently decreased mesangial cell viability and induced cell apoptosis. AGEs also induced ER stress signals in a time- and dose-dependent manner. Inhibition of ER stress with 4-phenylbutyric acid effectively inhibited the activation of eIF2α and CHOP signals and reversed AGEs-induced cell apoptosis. AGEs also activated LC-3 cleavage, increased Atg5 expression, and decreased p62 expression, which indicated the autophagy induction in mesangial cells. Inhibition of autophagy by Atg5 siRNAs transfection aggravated AGEs-induced mesangial cell apoptosis. Moreover, ER stress inhibition by 4-phenylbutyric acid significantly reversed AGEs-induced autophagy, but autophagy inhibition did not influence the AGEs-induced ER stress-related signals activation. These results suggest that AGEs induce mesangial cell apoptosis via an ER stress-triggered signaling pathway. Atg5-dependent autophagy plays a protective role. These findings may offer a new strategy against AGEs toxicity in the kidney. PMID:27665710

  18. Contribution of the toxic advanced glycation end-products-receptor axis in nonalcoholic steatohepatitis-related hepatocellular carcinoma.

    Science.gov (United States)

    Takino, Jun-Ichi; Nagamine, Kentaro; Hori, Takamitsu; Sakasai-Sakai, Akiko; Takeuchi, Masayoshi

    2015-10-18

    Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. The main etiologies of HCC are hepatitis B virus and hepatitis C virus (HCV), and non-hepatitis B/non-hepatitis C HCC (NBNC-HCC) has also been identified as an etiological factor. Although the incidence of HCV-related HCC in Japan has decreased slightly in recent years, that of NBNC-HCC has increased. The onset mechanism of NBNC-HCC, which has various etiologies, remains unclear; however, nonalcoholic steatohepatitis (NASH), a severe form of nonalcoholic fatty liver disease, is known to be an important risk factor for NBNC-HCC. Among the different advanced glycation end-products (AGEs) formed by the Maillard reaction, glyceraldehyde-derived AGEs, the predominant components of toxic AGEs (TAGE), have been associated with NASH and NBNC-HCC, including NASH-related HCC. Furthermore, the expression of the receptor for AGEs (RAGE) has been correlated with the malignant progression of HCC. Therefore, TAGE induce oxidative stress by binding with RAGE may, in turn, lead to adverse effects, such as fibrosis and malignant transformation, in hepatic stellate cells and tumor cells during NASH or NASH-related HCC progression. The aim of this review was to examine the contribution of the TAGE-RAGE axis in NASH-related HCC.

  19. Production and characterization of antibodies to advanced glycation products on proteins.

    Science.gov (United States)

    Nakayama, H; Taneda, S; Kuwajima, S; Aoki, S; Kuroda, Y; Misawa, K; Nakagawa, S

    1989-07-31

    Antibodies directed against advanced glycation products formed during Maillard reaction have been generated and characterized. These antibodies reacted specifically with advanced glycation products in common among proteins incubated with glucose, but not early-stage compounds such as a Schiff base adduct and Amadori rearrangement products. Incubation of bovine serum albumin with glucose caused a time-related increase in immunoreactivity and a concomitant increase in fluorescence intensity. These antibodies may serve as a useful tool to elucidate pathophysiological roles of advanced Maillard reaction in diabetic complications and aging processes.

  20. Reference values for the Chinese population of skin autofluorescence as a marker of advanced glycation end products accumulated in tissue

    NARCIS (Netherlands)

    Yue, X.; Hu, H.; Koetsier, M.; Graaff, R.; Han, C.

    2011-01-01

    Aim Advanced glycation end products play an important role in the pathophysiology of several chronic and age-related diseases, especially diabetes mellitus. Skin autofluorescence is a non-invasive method for assessing levels of tissue advanced glycation end products. This study aims to establish the

  1. Advanced glycation end products (AGEs) are cross-sectionally associated with insulin secretion in healthy subjects

    DEFF Research Database (Denmark)

    Forbes, Josephine M; Sourris, Karly C; de Courten, Maximilian;

    2013-01-01

    It has been postulated that chronic exposure to high levels of advanced glycation end products (AGEs), in particular from dietary sources, can impair insulin secretion. In the present study, we investigated the cross-sectional relationship between AGEs and acute insulin secretion during an intrav......It has been postulated that chronic exposure to high levels of advanced glycation end products (AGEs), in particular from dietary sources, can impair insulin secretion. In the present study, we investigated the cross-sectional relationship between AGEs and acute insulin secretion during...

  2. Role of myosin light chain and myosin light chain kinase in advanced glycation end product-induced endothelial hyperpermeability in vitro and in vivo.

    Science.gov (United States)

    Wu, Fan; Guo, Xiaohua; Xu, Jing; Wang, Weiju; Li, Bingling; Huang, Qiaobing; Su, Lei; Xu, Qiulin

    2016-03-01

    We have previously reported that advanced glycation end products activated Rho-associated protein kinase and p38 mitogen-activated protein kinase, causing endothelial hyperpermeability. However, the mechanisms involved were not fully clarified. Here, we explored the role of myosin light chain kinase in advanced glycation end product-induced endothelial hyperpermeability. Myosin light chain phosphorylation significantly increased by advanced glycation end products in endothelial cells in a time- and dose-dependent manner, indicating that myosin light chain phosphorylation is involved in the advanced glycation end product pathway. Advanced glycation end products also induced myosin phosphatase-targeting subunit 1 phosphorylation, and small interfering RNA knockdown of the receptor for advanced glycation end products, or blocking myosin light chain kinase with its inhibitor, ML-7, or small interfering RNA abated advanced glycation end product-induced myosin light chain phosphorylation. Advanced glycation end product-induced F-actin rearrangement and endothelial hyperpermeability were also diminished by inhibition of receptor for advanced glycation end product or myosin light chain kinase signalling. Moreover, inhibiting myosin light chain kinase with ML-7 or blocking receptor for advanced glycation end product with its neutralizing antibody attenuated advanced glycation end product-induced microvascular hyperpermeability. Our findings suggest a novel role for myosin light chain and myosin light chain kinase in advanced glycation end product-induced endothelial hyperpermeability.

  3. Induction of advanced glycation end products and alterations of the tensile properties of articular cartilage

    NARCIS (Netherlands)

    Chen, A.C.; Temple, M.M.; Ng, D.M.; Verzijl, N.; Groot, J. de; TeKoppele, J.M.; Sah, R.L.

    2002-01-01

    Objective. To determine whether increasing advanced glycation end products (AGEs) in bovine articular cartilage to levels present in aged human cartilage modulates the tensile biomechanical properties of the tissue. Methods. Adult bovine articular cartilage samples were incubated in a buffer solutio

  4. Effects of photobleaching on selected advanced glycation end products in the human lens

    DEFF Research Database (Denmark)

    Holm, Thomas; Raghavan, Cibin T; Nahomi, Rooban

    2015-01-01

    at examining the optical and biochemical effects of the proposed treatment.MethodsHuman donor lenses were photobleaced using a 445 nm cw laser. Lens optical quality was assessed before and after photobleaching by light transmission and scattering. The concentration of the advanced glycation end products (AGEs...

  5. Advanced glycation end products and the absence of premature atherosclerosis in glycogen storage disease Ia

    NARCIS (Netherlands)

    den Hollander, N. C.; Mulder, Douwe J.; Graaff, R.; Thorpe, S. R.; Baynes, J. W.; Smit, Gerrit; Smit, Andries

    2007-01-01

    Introducton: Despite their unfavourable cardiovascular risk profile, patients with glycogen storage disease type Ia (GSD Ia) do not develop premature atherosclerosis. We hypothesized that this paradox might be related to a decreased formation of advanced glycation end products (AGEs) resulting from

  6. Receptor for advanced glycation end product expression in experimental diabetic retinopathy

    NARCIS (Netherlands)

    Wang, Yumei; Hagen, Filanziska Vom; Pfister, Frederick; Bierhaus, Angelika; Feng, Yuxi; Gans, Reinhold; Hammes, Hans-Peter; Schleicher, E; Somoza,; Shieberle, P

    2008-01-01

    The advanced glycation end product (AGE)-receptor for AGE (RAGE) pathway is involved in the pathogenesis of diabetic microvascular damage. The special distribution of RAGE and its engagement has an impact on the development of diabetic retinopathy. In the present study, we used immunofluorescence an

  7. The Contribution of Advanced Glycation End product (AGE) accumulation to the decline in motor function

    NARCIS (Netherlands)

    Drenth, Hans; Zuidema, Sytse; Bunt, Steven; Bautmans, Ivan; van der Schans, Cees; Hobbelen, Hans

    2016-01-01

    Diminishing motor function is commonly observed in the elderly population and is associated with a wide range of adverse health consequences. Advanced Glycation End products (AGE's) may contribute to age-related decline in the function of cells and tissues in normal ageing. Although the negative eff

  8. The Contribution of advanced glycation End product (AGE) accumulation to the decline in motor function

    NARCIS (Netherlands)

    Drenth, Hans; Zuidema, Sytse; Bunt, Steven; Bautmans, Ivan; Schans, Cees van der; Hobbelen, Hans

    2016-01-01

    Diminishing motor function is commonly observed in the elderly population and is associated with a wide range of adverse health consequences. Advanced Glycation End products (AGE’s) may contribute to age-related decline in the function of cells and tissues in normal ageing. Although the negative eff

  9. Accumulation of Advanced Glycation End Products and Chronic Complications in ESRD Treated by Dialysis

    NARCIS (Netherlands)

    Meerwaldt, Robbert; Zeebregts, Clark J.; Navis, Gerjan; Hillebrands, Jan-Luuk; Lefrandt, Joop D.; Smit, Andries J.

    2009-01-01

    Cardiovascular and connective tissue disorders are very common in patients with end-stage renal disease (ESRD), and the accumulation of advanced glycation end products (AGEs) is significantly increased in these patients. Accumulation of AGEs is believed to have a role in tissue protein aging and the

  10. Effect of collagen turnover on the accumulation of advanced glycation end products

    NARCIS (Netherlands)

    Verzijl, N.; Groot, J. de; Thorpe, S.R.; Bank, R.A.; Shaw, J.N.; Lyons, T.J.; Bijlsma, J.W.J.; Lafeber, F.P.J.G.; Baynes, J.W.; TeKoppele, J.M.

    2000-01-01

    Collagen molecules in articular cartilage have an exceptionally long lifetime, which makes them susceptible to the accumulation of advanced glycation end products (AGEs). In fact, in comparison to other collagen-rich tissues, articular cartilage contains relatively high amounts of the AGE pentosidin

  11. Comparison of dietary agents' garlic and bitter melon on in vitro glycation and advanced glycation end products formation

    Directory of Open Access Journals (Sweden)

    Gini Garima

    2016-04-01

    Conclusions: M. charantia L seems to aggravate sugar mediated glycation of the protein and need further studies to pinpoint specific bioactive compounds responsible for the observed activities whereas aged garlic seems to have strong ant glycation properties. [Int J Basic Clin Pharmacol 2016; 5(2.000: 257-262

  12. Effect of dietary advanced glycation end products on postprandial appetite, inflammation, and endothelial activation in healthy overweight individuals

    DEFF Research Database (Denmark)

    Poulsen, Malene Wibe; Bak, Monika Judyta; Andersen, Jeanette Marker

    2014-01-01

    Advanced glycation end products (AGEs) formed in food during high-heat cooking may induce overeating and inflammation. We investigated whether AGE contents in a single meal affect postprandial appetite and markers of inflammation, endothelial activation, and oxidative stress....

  13. Advanced glycation end products induce differential structural modifications and fibrillation of albumin

    Science.gov (United States)

    Awasthi, Saurabh; Sankaranarayanan, Kamatchi; Saraswathi, N. T.

    2016-06-01

    Glycation induced amyloid fibrillation is fundamental to the development of many neurodegenerative and cardiovascular complications. Excessive non-enzymatic glycation in conditions such as hyperglycaemia results in the increased accumulation of advanced glycation end products (AGEs). AGEs are highly reactive pro-oxidants, which can lead to the activation of inflammatory pathways and development of oxidative stress. Recently, the effect of non-enzymatic glycation on protein structure has been the major research area, but the role of specific AGEs in such structural alteration and induction of fibrillation remains undefined. In this study, we determined the specific AGEs mediated structural modifications in albumin mainly considering carboxymethyllysine (CML), carboxyethyllysine (CEL), and argpyrimidine (Arg-P) which are the major AGEs formed in the body. We studied the secondary structural changes based on circular dichroism (CD) and spectroscopic analysis. The AGEs induced fibrillation was determined by Congo red binding and examination of scanning and transmission electron micrographs. The amyloidogenic regions in the sequence of BSA were determined using FoldAmyloid. It was observed that CEL modification of BSA leads to the development of fibrillar structures, which was evident from both secondary structure changes and TEM analysis.

  14. Acetoacetate promotes the formation of fluorescent advanced glycation end products (AGEs).

    Science.gov (United States)

    Bohlooli, Mousa; Ghaffari-Moghaddam, Mansour; Khajeh, Mostafa; Aghashiri, Zohre; Sheibani, Nader; Moosavi-Movahedi, Ali Akbar

    2016-12-01

    Acetoacetate (AA) is an important ketone body, which produces reactive oxygen species (ROS). Advanced glycation end products (AGEs) are defined as final products of glycation process whose production is influenced by the levels of ROS. The accumulation of AGEs in the body contributes to pathogenesis of many diseases including complications of diabetes, and Alzheimer's and Parkinson's disease. Here, we evaluated the impact of AA on production of AGEs upon incubation of human serum albumin (HSA) with glucose. The effect of AA on the AGEs formation of HSA was studied under physiological conditions after incubation with glucose for 35 days. The physical techniques including circular dichroism (CD) and fluorescence spectroscopy were used to assess the impact of AA on formation and structural changes of glycated HSA (GHSA). Our results indicated that the secondary and tertiary structural changes of GHSA were increased in the presence of AA. The fluorescence intensity measurements of AGEs also showed an increase in AGEs formation. Acetoacetate has an activator effect in formation of AGEs through ROS production. The presence of AA may result in enhanced glycation in the presence of glucose and severity of complications associated with accumulation of AGEs.

  15. Soluble Receptor for Advanced Glycation End Product: A Biomarker for Acute Coronary Syndrome

    Directory of Open Access Journals (Sweden)

    Louise J. N. Jensen

    2015-01-01

    Full Text Available The receptor of advanced glycation end products (RAGE and its ligands are linked to the pathogenesis of coronary artery disease (CAD, and circulating soluble receptor of advanced glycation end products (sRAGE, reflecting the RAGE activity, is suggested as a potential biomarker. Elevated sRAGE levels are reported in relation to acute ischemia and this review focuses on the role of sRAGE as a biomarker for the acute coronary syndrome (ACS. The current studies demonstrated that sRAGE levels are elevated in relation to ACS, however during a very narrow time period, indicating that the time of sampling needs attention. Interestingly, activation of RAGE may influence the pathogenesis and reflection in sRAGE levels in acute and stable CAD differently.

  16. Advanced glycation end products (AGEs) are cross-sectionally associated with insulin secretion in healthy subjects.

    Science.gov (United States)

    Forbes, Josephine M; Sourris, Karly C; de Courten, Maximilian P J; Dougherty, Sonia L; Chand, Vibhasha; Lyons, Jasmine G; Bertovic, David; Coughlan, Melinda T; Schlaich, Markus P; Soldatos, Georgia; Cooper, Mark E; Straznicky, Nora E; Kingwell, Bronwyn A; de Courten, Barbora

    2014-02-01

    It has been postulated that chronic exposure to high levels of advanced glycation end products (AGEs), in particular from dietary sources, can impair insulin secretion. In the present study, we investigated the cross-sectional relationship between AGEs and acute insulin secretion during an intravenous glucose tolerance test (IVGTT) and following a 75 g oral glucose tolerance test (OGTT) in healthy humans. We report the cross-sectional association between circulating AGE concentrations and insulin secretory function in healthy humans (17 F: 27 M, aged 30 ± 10 years) with a wide range of BMI (24.6-31.0 kg/m(2)). Higher circulating concentrations of AGEs were related to increased first phase insulin secretion during IVGTT (r = 0.43; p AGE (RAGE) isoforms (r = -0.39; p < 0.01). In conclusion, in healthy humans, we show a cross-sectional association between advanced glycation end products and acute insulin secretion during glucose tolerance testing.

  17. Advanced glycation end products: possible link between metabolic syndrome and periodontal diseases.

    Science.gov (United States)

    Pietropaoli, D; Monaco, A; Del Pinto, R; Cifone, M G; Marzo, G; Giannoni, M

    2012-01-01

    On a planetary scale, Metabolic Syndrome (MetS)is the third cause of inability after malnutrition and nicotinism, even higher than water shortage and sedentariness. In the USA, the prevalence is estimated at over 25 percent of the population; in Italy, it involves approximately 25 percent of men and even 27 percent of women. These are very high figures, corresponding to approximately 14 million affected individuals. The prevalence is alarming and must not be underestimated, particularly in the dental field, where more than one patient out of four sitting in a dentist chair is affected. The etiology of periodontal disease has not yet been clarified, and recently the idea to consider it as a multifactor pathology has been developed. Cofactors such as the formation of free radicals of oxygen (ROS), oxidative stress, lipid peroxidation, and formation of glycation end-products (AGEs) probably play an important role in the onset of periodontal disease. The AGEs are compounds physiologically produced by the cells. However, they accumulate and cause pro-inflammatory conditions, when the cellular clearance fails, or in hyperglycemic and oxidative states. All these conditions can be clinically summarized as Metabolic Syndrome. The purpose of this literature review is to establish a relationship between two pathologies with very high prevalence: Metabolic Syndrome and Periodontal Disorder. The literature seems to have clarified that MetS involves a pro-oxidation status, which induces AGE formation. AGEs play a very important role in the course and severity of periodontal diseases.

  18. Inhibition of advanced protein glycation by a Schiff base between aminoguanidine and pyridoxal.

    Science.gov (United States)

    Taguchi, T; Sugiura, M; Hamada, Y; Miwa, I

    1999-08-13

    Aminoguanidine is a well-known inhibitor of the formation of advanced glycation end products and is considered to be promising for the treatment of diabetic complications. We recently reported, however, that administration of aminoguanidine caused the formation of a Schiff base adduct between aminoguanidine and pyridoxal phosphate in the liver and kidney of mice and a concomitant decrease in the amount of liver pyridoxal phosphate. Our study led us to hypothesize that the Schiff base adduct and/or another Schiff base adduct formed from aminoguanidine and pyridoxal might be a better compound than aminoguanidine. In the present study, we examined the in vitro inhibitory potency of the latter adduct against advanced glycation end product formation and its effect on the tissue contents of pyridoxal and its phosphate. Aminoguanidine-pyridoxal phosphate adduct was not employed in this study because of its poor solubility in water. Aminoguanidine-pyridoxal adduct was hydrolyzed by only about 15% during 10 days at pH 7.4 and 37 degrees C. The adduct at 1 mM did not inhibit Amadori product formation induced by incubation of albumin with 100 mM mannose for 10 days. The adduct, when tested at 1 and 2 mM, dose-dependently inhibited advanced glycation end product formation induced by incubation of albumin with mannose; and the inhibitory potency of the adduct was similar to or higher than that of aminoguanidine. The presence of an appreciable amount of aminoguanidine-pyridoxal adduct in the kidney of mice given the adduct suggested that at least part of the adduct administered was absorbed from the gastrointestinal duct. The amounts of pyridoxal and its phosphate in tissues were not at all decreased by administration of the aminoguanidine-pyridoxal Schiff base. We conclude that the Schiff base may be a more promising inhibitor of advanced protein glycation than aminoguanidine.

  19. Induction of advanced glycation end products and alterations of the tensile properties of articular cartilage

    OpenAIRE

    Chen, A C; Temple, M.M.; Ng, D.M.; Verzijl, N; de Groot, J.; TeKoppele, J.M.; Sah, R.L.

    2002-01-01

    Objective. To determine whether increasing advanced glycation end products (AGEs) in bovine articular cartilage to levels present in aged human cartilage modulates the tensile biomechanical properties of the tissue. Methods. Adult bovine articular cartilage samples were incubated in a buffer solution with ribose to induce the formation of AGEs or in a control solution. Portions of cartilage samples were assayed for biochemical indices of AGEs and tested to assess their tensile biomechanical p...

  20. Assessment of advanced glycated end product accumulation in skin using auto fluorescence multispectral imaging

    OpenAIRE

    Larsson, Marcus; Favilla, Riccardo; Strömberg, Tomas

    2015-01-01

    Several studies have shown that advanced glycation end products (AGE) play a role in both the microvascular and macrovascular complications of diabetes and are closely linked to inflammation and atherosclerosis. AGEs accumulate in skin and can be detected using their auto fluorescence (AF).A significant correlation exists between AGE AF and the levels of AGEs as obtained from skin biopsies. A commercial device, the AGE Reader, has become available to assess skin AF for clinical purposes but, ...

  1. Advanced glycation end products measured by skin autofluorescence in a population with central obesity

    OpenAIRE

    den Engelsen, Corine; van den Donk, Maureen; Gorter, Kees J; Salomé, Philippe L; Rutten, Guy E

    2012-01-01

    Accumulation of advanced glycation end products (AGEs) is enhanced by chronic hyperglycemia and oxidative stress and this process may contribute to the pathogenesis of vascular disease. Skin autofluorescence (AF), a measure of accumulation of AGEs in skin collagen, is associated with vascular disease in patients with diabetes.   Because central obesity enhances oxidative stress people with central obesity might already have increased accumulation of AGEs before diabetes or cardiovascular dise...

  2. Soluble receptor for advanced glycation end products and risk of liver cancer

    OpenAIRE

    2013-01-01

    Binding of advanced glycation end products (AGEs) to their receptor (RAGE) increases oxidative stress and inflammation, and may be involved in liver injury and subsequent carcinogenesis. Soluble RAGE (sRAGE) may neutralize the effects mediated by AGEs/RAGE complex. Epidemiologic studies examining sRAGE or AGEs in association with liver cancer are lacking. We examined the associations between prediagnostic serum concentrations of sRAGE or Nε-(carboxymethyl)-lysine (CML)-AGE and hepatocellular ...

  3. Receptor for advanced glycation end products is detrimental during influenza A virus pneumonia☆

    OpenAIRE

    2009-01-01

    Pneumonia caused by influenza A virus (IAV) can have devastating effects, resulting in respiratory failure and death. The idea that a new influenza pandemic might occur in the near future has triggered renewed interests in IAV infection. The receptor for advanced glycation end products (RAGE) is expressed on different cell types and plays a key role in diverse inflammatory processes. We here investigated the role of RAGE in the host response to IAV pneumonia using wild-type (wt) and RAGE defi...

  4. Quercetin as a finer substitute to aminoguanidine in the inhibition of glycation products.

    Science.gov (United States)

    Ashraf, Jalaluddin M; Shahab, Uzma; Tabrez, Shams; Lee, Eun Ju; Choi, Inho; Ahmad, Saheem

    2015-01-01

    Non-enzymatic glycation is the addition of a free carbonyl group of a reducing sugar to the free amino groups of proteins, which results in the formation of early and advanced glycation end-products (AGEs). Glycation reaction is profoundly associated with diabetes and its secondary complications, such as nephropathy and neuropathy. Glyoxal is a carbonyl species that reacts rapidly with the free amino groups of proteins to form AGEs. While the formation of AGEs with various glycating agents has previously been demonstrated, no extensive studies have been conducted to assess the role of quercetin in all three stages of glycation (early, intermediate and late). In this study, we report the glycation of HSA (human serum albumin) and its characterization by several spectroscopic techniques. Furthermore, inhibition of products at all stages of glycation was studied by various assays. Spectroscopic analysis suggests structural perturbations in the HSA macromolecule as a result of modification, which might be due to the generation of free radicals and the formation of AGEs. Inhibition in the formation of glycation has established that quercetin is a better and a more potent antiglycating agent than aminoguanidine at all stages of glycation.

  5. Skin autofluorescence, a non-invasive marker of advanced glycation end products: clinical relevance and limitations.

    Science.gov (United States)

    Da Moura Semedo, Cidila; Webb, M'Balu; Waller, Helen; Khunti, Kamlesh; Davies, Melanie

    2017-01-31

    Advanced glycation end products (AGEs) are protein-bound compounds derived from glycaemic and oxidative stress that contain fluorescent properties, which can be non-invasively measured as skin autofluorescence (SAF) by the AGE Reader. SAF has been demonstrated to be a biomarker of cumulative skin AGEs and potentially may be a better predictor for the development of chronic complications and mortality in diabetes than glycated haemoglobin A1c. However, there are several confounding factors that should be assessed prior to its broader application: these include presence of other fluorescent compounds in the skin that might be measured (eg, fluorophores), skin pigmentation and use of skin creams. The aim of this article is to provide a theoretical background of this newly developed method, evaluate its clinical relevance and discuss the potential confounding factors that need further analysis.

  6. Advanced Glycation End Products, Inflammation, and Chronic Metabolic Diseases: Links in a Chain?

    Science.gov (United States)

    Davis, Kathleen E; Prasad, Chandan; Vijayagopal, Parakat; Juma, Shanil; Imrhan, Victorine

    2016-01-01

    Advanced glycation end products (AGEs) are a diverse group of compounds produced when reducing sugars react with proteins or other compounds to form glycosylated molecules. AGEs may form endogenously, and glycation of molecules may negatively affect their function. AGEs may also be consumed in food form with dietary AGEs reported to be particularly high in foods treated with high heat: baked, broiled, grilled, and fried foods. Whether dietary AGEs are absorbed in significant quantities and whether they are harmful if absorbed is a question under current debate. The American Diabetes Association makes no recommendation regarding avoidance of these foods, but many researchers are concerned that they may be pro-inflammatory and way worsen cardiac function, kidney function, diabetes and its complications and may even contribute to obesity.

  7. Increased accumulation of skin advanced glycation end-products precedes and correlates with clinical manifestation of diabetic neuropathy

    NARCIS (Netherlands)

    Meerwaldt, R; Links, TP; Graaff, R; Hoogenberg, K; Lefrandt, JD; Baynes, JW; Gans, ROB; Smit, AJ

    2005-01-01

    Aims/hypothesis: The accumulation of AGE is related to the progression of the renal, retinal and vascular complications of diabetes. However, the relationship with diabetic neuropathy remains unclear. We recently showed that skin autofluorescence, measured non-invasively with an AutoFluorescence Rea

  8. A Perspective on the Maillard Reaction and the Analysis of Protein Glycation by Mass Spectrometry: Probing the Pathogenesis of Chronic Disease

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qibin; Ames, Jennifer M.; Smith, Richard D.; Baynes, John; Metz, Thomas O.

    2008-12-18

    The Maillard reaction, starting from the glycation of protein and progressing to the formation of advanced glycation end-products (AGEs), is implicated in the development of complications of diabetes mellitus, as well as in the pathogenesis of cardiovascular, renal, and neurodegenerative diseases. In this perspective review, we provide on overview on the relevance of the Maillard reaction in the pathogenesis of chronic disease and discuss traditional approaches and recent developments in the analysis of glycated proteins by mass spectrometry. We propose that proteomics approaches, particularly bottom-up proteomics, will play a significant role in analyses of clinical samples leading to the identification of new markers of disease development and progression.

  9. Rifampicin reduces advanced glycation end products and activates DAF-16 to increase lifespan in Caenorhabditis elegans.

    Science.gov (United States)

    Golegaonkar, Sandeep; Tabrez, Syed S; Pandit, Awadhesh; Sethurathinam, Shalini; Jagadeeshaprasad, Mashanipalya G; Bansode, Sneha; Sampathkumar, Srinivasa-Gopalan; Kulkarni, Mahesh J; Mukhopadhyay, Arnab

    2015-06-01

    Advanced glycation end products (AGEs) are formed when glucose reacts nonenzymatically with proteins; these modifications are implicated in aging and pathogenesis of many age-related diseases including type II diabetes, atherosclerosis, and neurodegenerative disorders. Thus, pharmaceutical interventions that can reduce AGEs may delay age-onset diseases and extend lifespan. Using LC-MS(E), we show that rifampicin (RIF) reduces glycation of important cellular proteins in vivo and consequently increases lifespan in Caenorhabditis elegans by up to 60%. RIF analog rifamycin SV (RSV) possesses similar properties, while rifaximin (RMN) lacks antiglycation activity and therefore fails to affect lifespan positively. The efficacy of RIF and RSV as potent antiglycating agents may be attributed to the presence of a p-dihydroxyl moiety that can potentially undergo spontaneous oxidation to yield highly reactive p-quinone structures, a feature absent in RMN. We also show that supplementing rifampicin late in adulthood is sufficient to increase lifespan. For its effect on longevity, rifampicin requires DAF-18 (nematode PTEN) as well as JNK-1 and activates DAF-16, the FOXO homolog. Interestingly, the drug treatment modulates transcription of a different subset of DAF-16 target genes, those not controlled by the conserved Insulin-IGF-1-like signaling pathway. RIF failed to increase the lifespan of daf-16 null mutant despite reducing glycation, showing thereby that DAF-16 may not directly affect AGE formation. Together, our data suggest that the dual ability to reduce glycation in vivo and activate prolongevity processes through DAF-16 makes RIF and RSV effective lifespan-extending interventions.

  10. Glycolaldehyde-derived advanced glycation end products (glycol-AGEs)-induced vascular smooth muscle cell dysfunction is regulated by the AGES-receptor (RAGE) axis in endothelium.

    Science.gov (United States)

    Nam, Mi-Hyun; Son, Won-Rak; Lee, Young Sik; Lee, Kwang-Won

    Advanced glycation end-products (AGEs) are involved in the development of vascular smooth muscle cell (VSMC) dysfunction and the progression of atherosclerosis. However, AGEs may indirectly affect VSMCs via AGEs-induced signal transduction between monocytes and human umbilical endothelial cells (HUVECs), rather than having a direct influence. This study was designed to elucidate the signaling pathway underlying AGEs-RAGE axis influence on VSMC dysfunction using a co-culture system with monocytes, HUVECs and VSMCs. AGEs stimulated production of reactive oxygen species and pro-inflammatory mediators such as tumor necrosis factor-α and interleukin-1β via extracellular-signal-regulated kinases phosphorylation and nuclear factor-κB activation in HUVECs. It was observed that AGEs-induced pro-inflammatory cytokines increase VSMC proliferation, inflammation and vascular remodeling in the co-culture system. This result implies that RAGE plays a role in AGEs-induced VSMC dysfunction. We suggest that the regulation of signal transduction via the AGEs-RAGE axis in the endothelium can be a therapeutic target for preventing atherosclerosis.

  11. Evaluation of the Antioxidant and Anti-glication Effects of the Hexane Extract from Piper auritum Leaves in Vitro and Beneficial Activity on Oxidative Stress and Advanced Glycation End-Product-Mediated Renal Injury in Streptozotocin-Treated Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Adriana Maria Neira Gonzalez

    2012-10-01

    Full Text Available The aim of this study was to investigate the antioxidant activity of hexane extracts from leaves of Piper auritum (HS. Eight complementary in vitro test methods were used, including inhibition of DPPH· radicals, nitric oxide, superoxide anion, ion-chelating, ABTS, oxygen radical absorbance capacity, β-carotene bleaching and peroxy radical scavenging. The results indicated that HS possesses high antioxidant activity. To add to these finding we tested the effect against oxidative stress in liver, pancreas and kidney in diabetic rats. Low levels of SOD, CAT, GPx and GSH in diabetic rats were reverted to near normal values after treatment with HS. These results suggest that P. auritum prevents oxidative stress, acting as a suppressor of liver cell damage. Given the link between glycation and oxidation, we proposed that HS might possess significant in vitro antiglycation activity. Our data confirmed the inhibitory effect of HS on bovine serum albumin, serum glycosylated protein, glycation of LDL, and glycation hemoglobin. The effect of HS on diabetic renal damage was investigated using streptozotocin-induced diabetic rats. The oral administration of HS at a dose of 200 and 400 mg/kg body weight/day for 28 days significantly reduced advanced glycation endproduct (AGE formation, elevated renal glucose and thiobarbituric acid-reactive substance levels in the kidneys of diabetic rats. This implies that HS would alleviate the oxidative stress under diabetes through the inhibition of lipid peroxidation. These findings indicate that oxidative stress is increased in the diabetic rat kidney and that HS can prevent renal damage associated with diabetes by attenuating the oxidative stress.

  12. Evaluation of the antioxidant and anti-glication effects of the hexane extract from Piper auritum leaves in vitro and beneficial activity on oxidative stress and advanced glycation end-product-mediated renal injury in streptozotocin-treated diabetic rats.

    Science.gov (United States)

    Perez Gutierrez, Rosa Martha; Flores Cotera, Luis B; Gonzalez, Adriana Maria Neira

    2012-10-09

    The aim of this study was to investigate the antioxidant activity of hexane extracts from leaves of Piper auritum (HS). Eight complementary in vitro test methods were used, including inhibition of DPPH· radicals, nitric oxide, superoxide anion, ion-chelating, ABTS, oxygen radical absorbance capacity, β-carotene bleaching and peroxy radical scavenging. The results indicated that HS possesses high antioxidant activity. To add to these finding we tested the effect against oxidative stress in liver, pancreas and kidney in diabetic rats. Low levels of SOD, CAT, GPx and GSH in diabetic rats were reverted to near normal values after treatment with HS. These results suggest that P. auritum prevents oxidative stress, acting as a suppressor of liver cell damage. Given the link between glycation and oxidation, we proposed that HS might possess significant in vitro antiglycation activity. Our data confirmed the inhibitory effect of HS on bovine serum albumin, serum glycosylated protein, glycation of LDL, and glycation hemoglobin. The effect of HS on diabetic renal damage was investigated using streptozotocin-induced diabetic rats. The oral administration of HS at a dose of 200 and 400 mg/kg body weight/day for 28 days significantly reduced advanced glycation endproduct (AGE) formation, elevated renal glucose and thiobarbituric acid-reactive substance levels in the kidneys of diabetic rats. This implies that HS would alleviate the oxidative stress under diabetes through the inhibition of lipid peroxidation. These findings indicate that oxidative stress is increased in the diabetic rat kidney and that HS can prevent renal damage associated with diabetes by attenuating the oxidative stress.

  13. Receptor for Advanced Glycation End Products Regulates Leukotriene B4 Receptor 1 Signaling.

    Science.gov (United States)

    Ichiki, Takako; Koga, Tomoaki; Yokomizo, Takehiko

    2016-12-01

    Leukotriene B4 receptor 1 (BLT1), a high-affinity G protein-coupled receptor (GPCR) for leukotriene B4 (LTB4), plays important roles in inflammatory and immune reactions. Although the LTB4-BLT1 axis is known to promote inflammation, the binding proteins that modulate LTB4-BLT1 signaling have not been identified. Recently, we discovered that receptor for advanced glycation end products (RAGE) interacts with BLT1 and modulates LTB4-BLT1 signaling. We propose RAGE as a new class of GPCR modulator and a new target of future GPCR studies.

  14. Short-term effects of dietary advanced glycation end products in rats

    DEFF Research Database (Denmark)

    Poulsen, Malene Wibe; Andersen, Jeanette Marker; Hedegaard, Rikke Susanne Vingborg

    2016-01-01

    Dietary advanced glycation end products (AGE) formed during heating of food have gained interest as potential nutritional toxins with adverse effects on inflammation and glucose metabolism. In the present study, we investigated the short-term effects of high and low molecular weight (HMW and LMW......) dietary AGE on insulin sensitivity, expression of the receptor for AGE (RAGE), the AGE receptor 1 (AGER1) and TNF-α, F2-isoprostaglandins, body composition and food intake. For 2 weeks, thirty-six Sprague-Dawley rats were fed a diet containing 20 % milk powder with different proportions of this being...

  15. The distribution of advanced glycation end products and their receptor in the gastrointestinal tract in the rats

    DEFF Research Database (Denmark)

    Chen, Pengmin; Zhao, Jingbo; Gregersen, Hans

    2012-01-01

    To investigate the distribution of advanced glycation end products (AGEs) and their receptor (RAGE) in the gastrointestinal (GI) tract to provide a basis for further study of the association between AGE/RAGE and diabetic GI dysfunction. METHODS: The distribution of AGEs [N epsilon-(carboxymethyl)......To investigate the distribution of advanced glycation end products (AGEs) and their receptor (RAGE) in the gastrointestinal (GI) tract to provide a basis for further study of the association between AGE/RAGE and diabetic GI dysfunction. METHODS: The distribution of AGEs [N epsilon...

  16. Glycated albumin is the preferred marker for assessing glycaemic control in advanced chronic kidney disease.

    Science.gov (United States)

    Vos, Frederiek E; Schollum, John B; Walker, Robert J

    2011-12-01

    Diabetic nephropathy is the most common aetiology of end-stage kidney disease (ESKD). Strict glycaemic control reduces the development and progression of diabetes-related complications, and there is evidence that improved metabolic control improves outcomes in diabetic subjects with advanced chronic kidney disease (CKD). Glycaemic control in people with kidney disease is complex. Changes in glucose and insulin homeostasis may occur as a consequence of loss of kidney function and dialysis. The reliability of measures of long-term glycaemic control is affected by CKD and the accuracy of glycated haemoglobin (HbA1c) in the setting of CKD and ESKD is questioned. Despite the altered character of diabetes in CKD, current guidelines for diabetes management are not specifically adjusted to this patient group. The validity of indicators of longer term glycaemic control has been the focus of increased recent research. This review discusses the current understanding of commonly used indicators of metabolic control (HbA1c, fructosamine, glycated albumin) in the setting of advanced CKD (Stages 4 and 5, glomerular filtration rate <30 mL/min/1.73m(2)).

  17. Role of the receptor for advanced glycation end products in hepatic fibrosis

    Institute of Scientific and Technical Information of China (English)

    Christina Lohwasser; Daniel Neureiter; Yury Popov; Michael Bauer; Detlef Schuppan

    2009-01-01

    AIM: To study the role of advanced glycation end products (AGE) and their specific receptor (RAGE) in the pathogenesis of liver fibrogenesis. METHODS: In vitro RAGE expression and extracellular matrix-related gene expression in both rat and human hepatic stellate cells (HSC) were measured after stimulation with the two RAGE ligands, advanced glycation end product-bovine serum albumin (AGEBSA) and Nε-(carboxymethyl) lysine (CML)-BSA, or with tumor necrosis factor-α (TNF-α). In vivo RAGE expression was examined in models of hepatic fibrosis induced by bile duct ligation or thioacetamide. The effects of AGE-BSA and CML-BSA on HSC proliferation, signal transduction and profibrogenic gene expression were studied in vitro. RESULTS: In hepatic fibrosis, RAGE expression was enhanced in activated HSC, and also in endothelial cells, inflammatory cells and activated bile duct epithelia. HSC expressed RAGE which was upregulated after stimulation with AGE-BSA, CML-BSA, and TNF-α. RAGE stimulation with AGE-BSA and CML-BSA did not alter HSC proliferation, apoptosis, fibrogenic signal transduction and fibrosis- or fibrolysis-related gene expression, except for marginal upregulation of procollagen α1(Ⅰ) mRNA by AGE-BSA. CONCLUSION: Despite upregulation of RAGE in activated HSC, RAGE stimulation by AGE does not alter their fibrogenic activation. Therefore, RAGE does not contribute directly to hepatic fibrogenesis.

  18. Effects of Aging and Advanced Glycation on Gene Expression in Cerebrum and Spleen of Mice

    Institute of Scientific and Technical Information of China (English)

    YUE-XIN LIANG; ZHEN WANG; DIAN-DONG LI; JIAN-MIN JIANG; RONG-GUANG SHAO

    2003-01-01

    Objective To analyze the effects of aging or advanced glycation on gene expression in the cerebrum and spleen of female C57BL/6J mice. Methods The gene expression profile was determined by using cDNA expression arrays containing 588 cDNA. Results Aging and advanced glycation resulted in differential gene expression patterns of cerebrum and spleen compared with young mice. Among the 80 genes detected in cerebrum, 43 exhibited a change in mRNA ratios with aging or treatment. Thirty-four changes (79%) were common in aged and D-galactose treated mice,whereas the cerebrum from aged and AGE-lysine treated mice showed common changes in expression of 38 genes(88%). Of the 86 genes detected in spleen, 29 (34%) displayed an age-related decrease in expression, whereas 3 (3%) displayed an increase in expression levels with aging. Eighteen genes from the detectable genes exhibited expression changes in both cerebrum and spleen of mice.Conclusions The gene expression profiles of D-galactose and AGE-lysine treated mice resemble those of aged mice. Use of cDNA hybridization arrays may provide a promising tool to explore the mechanism of aging at a molecular level.

  19. Impairment of human keratinocyte mobility and proliferation by advanced glycation end products-modified BSA.

    Science.gov (United States)

    Zhu, Ping; Yang, Chuan; Chen, Li-Hong; Ren, Meng; Lao, Guo-Juan; Yan, Li

    2011-07-01

    The migration and proliferation of keratinocytes is critical to wound re-epithelialization and defects in this function are associated with the clinical phenomenon of chronic non-healing wounds. Advanced glycation end products (AGEs) occur through non-enzymatic glycation of long-lived proteins in diabetes and play important roles in diabetic complications. However, specific roles for AGEs in keratinocyte migration and proliferation, and the underlying molecular mechanisms, have not been fully established. The aim of the current study was to elucidate the interaction between AGE-modified bovine serum albumin (AGE-BSA) and keratinocytes. As a result, we found that AGE-BSA had no effect on the viability of keratinocytes for up to 48 h of incubation with 50 μg/ml of AGE-BSA. AGE-BSA (but not non-glycated BSA) exerted a concentration-dependent suppression of keratinocyte migration at a range of concentrations. The expression of matrix metalloproteinase-9 (MMP-9) was significantly up-regulated in keratinocytes incubated with increasing AGE-BSA, but tissue inhibitor of metalloproteinases-1 (TIMP-1) expression was down-regulated. AGE-BSA also profoundly depressed phospho-focal adhesion kinase-Tyr397 (p-FAK) and α2β1 integrin expression, while total-FAK expression levels remained constant, in keratinocytes. The proliferative capacity of keratinocytes was diminished after 72 h AGE-BSA incubation. Taken together, these findings suggested that in the presence of AGE-BSA, keratinocytes lose their migratory and proliferation abilities. These data also indicated that, in the context of the chronic hyperglycemia in diabetes, the effects of AGE-BSA on keratinocyte migration might be mediated through MMP-9/TIMP-1, p-FAK and α2β1 integrin.

  20. Accumulation of advanced glycation end products and chronic complications in ESRD treated by dialysis.

    Science.gov (United States)

    Meerwaldt, Robbert; Zeebregts, Clark J; Navis, Gerjan; Hillebrands, Jan-Luuk; Lefrandt, Joop D; Smit, Andries J

    2009-01-01

    Cardiovascular and connective tissue disorders are very common in patients with end-stage renal disease (ESRD), and the accumulation of advanced glycation end products (AGEs) is significantly increased in these patients. Accumulation of AGEs is believed to have a role in tissue protein aging and the pathogenesis of such age-related diseases as diabetes and ESRD. AGEs accumulate in patients with ESRD as a result of nonenzymatic glycation, oxidative stress, and diminished clearance of AGE precursors. Some AGEs show characteristic brown pigmentation and fluorescence, form protein-protein cross-links, and may ligate with AGE-specific receptors, inducing oxidative stress and cytokine production. This review focuses on the clinical relevance of AGE accumulation in patients with ESRD treated by dialysis for the development of long-term complications. The formation and accumulation of AGEs in patients with ESRD are discussed, as well as the relationship between AGE accumulation and such major complications of ESRD as cardiovascular and connective tissue disorders.

  1. Ameliorating Effect of Akebia quinata Fruit Extracts on Skin Aging Induced by Advanced Glycation End Products

    Directory of Open Access Journals (Sweden)

    Seoungwoo Shin

    2015-11-01

    Full Text Available The accumulation of free radicals and advanced glycation end products (AGEs in the skin plays a very important role in skin aging. Both are known to interact with each other. Therefore, natural compounds or extracts that possess both antioxidant and antiglycation activities might have great antiageing potential. Akebia quinata fruit extract (AQFE has been used to treat urinary tract inflammatory disease in traditional Korean and Chinese medicines. In the present study, AQFE was demonstrated to possess antioxidant and antiglycation activity. AQFE protects human dermal fibroblasts (HDFs from oxidative stress and inhibits cellular senescence induced by oxidative stress. We also found that AQFE inhibits glycation reaction between BSA and glucose. The antiglycation activity of AQFE was dose-dependent. In addition, the antiglycation activity of AQFE was confirmed in a human skin explant model. AQFE reduced CML expression and stimulated fibrillin-1 expression in comparison to the methyglyoxal treatment. In addition, the possibility of the extract as an anti-skin aging agent has also been clinically validated. Our analysis of the crow’s feet wrinkle showed that there was a decrease in the depth of deep furrows in RI treated with AQFE cream over an eight-week period. The overall results suggest that AQFE may work as an anti-skin aging agent by preventing oxidative stress and other complications associated with AGEs formation.

  2. Ameliorating Effect of Akebia quinata Fruit Extracts on Skin Aging Induced by Advanced Glycation End Products.

    Science.gov (United States)

    Shin, Seoungwoo; Son, Dahee; Kim, Minkyung; Lee, Seungjun; Roh, Kyung-Baeg; Ryu, Dehun; Lee, Jongsung; Jung, Eunsun; Park, Deokhoon

    2015-11-12

    The accumulation of free radicals and advanced glycation end products (AGEs) in the skin plays a very important role in skin aging. Both are known to interact with each other. Therefore, natural compounds or extracts that possess both antioxidant and antiglycation activities might have great antiageing potential. Akebia quinata fruit extract (AQFE) has been used to treat urinary tract inflammatory disease in traditional Korean and Chinese medicines. In the present study, AQFE was demonstrated to possess antioxidant and antiglycation activity. AQFE protects human dermal fibroblasts (HDFs) from oxidative stress and inhibits cellular senescence induced by oxidative stress. We also found that AQFE inhibits glycation reaction between BSA and glucose. The antiglycation activity of AQFE was dose-dependent. In addition, the antiglycation activity of AQFE was confirmed in a human skin explant model. AQFE reduced CML expression and stimulated fibrillin-1 expression in comparison to the methyglyoxal treatment. In addition, the possibility of the extract as an anti-skin aging agent has also been clinically validated. Our analysis of the crow's feet wrinkle showed that there was a decrease in the depth of deep furrows in RI treated with AQFE cream over an eight-week period. The overall results suggest that AQFE may work as an anti-skin aging agent by preventing oxidative stress and other complications associated with AGEs formation.

  3. Ferulic acid prevents methylglyoxal-induced protein glycation, DNA damage, and apoptosis in pancreatic β-cells.

    Science.gov (United States)

    Sompong, Weerachat; Cheng, Henrique; Adisakwattana, Sirichai

    2017-02-01

    Methylglyoxal (MG) can react with amino acids of proteins to induce protein glycation and consequently the formation of advanced glycation end-products (AGEs). Previous studies reported that ferulic acid (FA) prevented glucose-, fructose-, and ribose-induced protein glycation. In this study, FA (0.1-1 mM) inhibited MG-induced protein glycation and oxidative protein damage in bovine serum albumin (BSA). Furthermore, FA (0.0125-0.2 mM) protected against lysine/MG-mediated oxidative DNA damage, thereby inhibiting superoxide anion and hydroxyl radical generation during lysine and MG reaction. In addition, FA did not have the ability to trap MG. Finally, FA (0.1 mM) pretreatment attenuated MG-induced decrease in cell viability and prevented MG-induced cell apoptosis in pancreatic β-cells. The results suggest that FA is capable of protecting β-cells from MG-induced cell damage during diabetes.

  4. [Glycation of extracellular matrix proteins and its role in atherosclerosis].

    Science.gov (United States)

    Kuzan, Aleksandra; Chwiłkowska, Agnieszka; Kobielarz, Magdalena; Pezowicz, Celina; Gamian, Andrzej

    2012-10-29

    Glycation consists in formation of advanced glycation end-products (AGE) during non-enzymatic reaction between reducing sugars and proteins, lipids or nucleic acids. This review is focused mainly on glycation of collagen and its role in acceleration of vascular disease. Collagen is an extracellular matrix protein characterized by unique structure forming fibrils with great anti-tensile and anti-breaking strength. The protein builds the connective tissue and is responsible for biomechanical properties of blood vessels. It is reported that higher content of glycated collagen correlates with lower elasticity and greater toughness of the vessel walls and, as a consequence, a faster rate of atherosclerosis development. Numerous mechanisms connected with AGE formation are involved in atherogenesis, among others: receptor-mediated production of free radicals, triggering an inflammatory process, activation of leukocytes and thrombocytes, facilitation of LDL binding, change in level of growth factors, adhesion molecules, MMP and some other proteins' expression. The coverages allow the development of therapeutic strategies to prevent or slow down the pathological processes connected with glycation of collagen and other proteins in the artery wall. The main strategies are based on limitation of exogenous AGE, consumption of products which contain rutin, treatment with drugs which inhibit AGE formation, such as pyridoxamine, and chemicals which are able to cleave already formed AGE protein-protein crosslinks, such as ALT-711.

  5. Skin autofluorescence as a measure of advanced glycation end products deposition is elevated in peripheral artery disease

    NARCIS (Netherlands)

    De Vos, Lisanne C.; Noordzij, Marjon J.; Mulder, Douwe J.; Smit, Andries J.; Lutgers, Helen L.; Dullaart, Robin P.F.; Kamphuisen, Pieter W.; Zeebregts, Clark J.; Lefrandt, Johan

    2013-01-01

    OBJECTIVE: Evidence for an important role of advanced glycation end products (AGEs) in the development of atherosclerosis and cardiovascular disease beyond diabetes mellitus and renal disease is growing. Skin autofluorescence (SAF) is a validated noninvasive measure of tissue AGEs. We hypothesized t

  6. Skin autofluorescence, a measure of cumulative metabolic stress and advanced glycation end products, predicts mortality in hemodialysis patients

    NARCIS (Netherlands)

    Meerwaldt, R; Hartog, JWL; Graaff, R; Huisman, RJ; Links, TP; den Hollander, NC; Thorpe, [No Value; Baynes, JW; Navis, G; Gans, ROB; Smit, AJ

    2005-01-01

    Tissue advanced glycation end products (AGE) are a measure of cumulative metabolic stress and trigger cytokines driven inflammatory reactions. AGE are thought to contribute to the chronic complications of diabetes and ESRD. Tissue autofluorescence is related to the accumulation of AGE. Therefore, sk

  7. Consumption of a diet low in advanced glycation end products for 4 weeks improves insulin sensitivity in overweight women

    DEFF Research Database (Denmark)

    Mark, Alicja Budek; Poulsen, Malene Wibe; Andersen, Stine;

    2014-01-01

    OBJECTIVE High-heat cooking of food induces the formation of advanced glycation end products (AGEs), which are thought to impair glucose metabolism in type 2 diabetic patients. High intake of fructose might additionally affect endogenous formation of AGEs. This parallel intervention study...

  8. Accumulation of Advanced Glycation End Products as a Molecular Mechanism for Aging as a Risk Factor in Osteoarthritis

    NARCIS (Netherlands)

    Groot, J. de; Verzijl, N.; Wenting-Wijk, M.J.G. van; Jacobs, K.M.G.; El, B. van; Roermund, P.M. van; Bank, R.A.; Bijlsma, J.W.J.; TeKoppele, J.M.; Lafeber, F.P.J.G.

    2004-01-01

    Objective. Osteoarthritis (OA) is one of the most prevalent and disabling chronic conditions affecting the elderly. Its etiology is largely unknown, but age is the most prominent risk factor. The current study was designed to test whether accumulation of advanced glycation end products (AGEs), which

  9. Tissue advanced glycation end products are associated with diastolic function and aerobic exercise capacity in diabetic heart failure patients

    NARCIS (Netherlands)

    Willemsen, Suzan; Hartog, Jasper W. L.; Hummel, Yoran M.; van Ruijven, Marieke H. I.; van der Horst, Iwan C. C.; van Veldhuisen, Dirk J.; Voors, Adriaan A.

    2011-01-01

    Aims Advanced glycation end products (AGEs) are increased in patients with diabetes and are associated with diastolic dysfunction through the formation of collagen crosslinks in the heart. The association among AGEs, diastolic function, and aerobic capacity in heart failure (HF) patients with and wi

  10. The influence of body mass index on the accumulation of advanced glycation end products in hemodialysis patients

    NARCIS (Netherlands)

    Arsov, S.; Trajceska, L.; van Oeveren, W.; Smit, A. J.; Dzekova, P.; Stegmayr, B.; Sikole, A.; Rakhorst, G.; Graaff, R.

    2015-01-01

    BACKGROUND/OBJECTIVES: The level of skin autofluorescence (AF) at a given moment is an independent predictor of mortality in hemodialysis (HD) patients. Skin AF is a measure of the accumulation of advanced glycation end products (AGEs). The aim of the study was to estimate the influence of nutrition

  11. Soluble receptor for advanced glycation end products as an indicator of pulmonary vascular injury after cardiac surgery

    NARCIS (Netherlands)

    S. Tuinman (Sietske); A.D. Cornet (Alexander); M.T. Kuipers (Maria); A.P.J. Vlaar (Alexander); M.J. Schultz (Marcus); A. Beishuizen (Auke); A.B.J. Groeneveld (Johan); N.P. Juffermans (Nicole)

    2013-01-01

    textabstractBackground: Cardiac surgery is frequently complicated by an acute vascular lung injury and this may be mediated, at least in part, by the (soluble) receptor for advanced glycation end products (sRAGE).Methods: In two university hospital intensive care units, circulating sRAGE was measure

  12. Serum levels of advanced glycation end products are associated with left ventricular diastolic function in patients with type 1 diabetes

    DEFF Research Database (Denmark)

    Berg, T J; Snorgaard, O; Faber, J;

    1999-01-01

    Impairment of left ventricular diastolic function, possibly caused by increased collagen cross-linking of the cardiac muscle, is common in patients with type 1 diabetes even without coronary artery disease. Advanced glycation end products (AGEs) cross-link tissue collagen and are found within...

  13. Role of zinc along with ascorbic acid and folic acid during long-term in vitro albumin glycation.

    Science.gov (United States)

    Tupe, Rashmi Santosh; Agte, Vaishali Vilas

    2010-02-01

    The present study aimed to investigate the role of Zn alone and in the presence of ascorbic acid (AA) and folic acid (FA) in albumin glycation. Glycation was performed by incubations of bovine serum albumin with glucose at 37 degrees C along with Zn, AA or FA separately and Zn + AA or Zn + FA for 150 d. Glycation-mediated modifications were monitored as fluorescence of advanced glycation endproducts, carbonyl formation, beta aggregation (thioflavin T and Congo red dyes), albumin-bound Zn, thiol groups and glycated aggregate's toxicity in HepG2 cells. Zn inhibited glycation and beta aggregation, probably due to observed higher protein-bound Zn. It also protected protein thiols and increased cell survival. AA and FA enhanced glycation, which was lowered in Zn-co-incubated samples. FA increased albumin-bound Zn and showed maximum cell survival. Although these results warrant further in vivo investigation, the present data help in the understanding of the interplay of Zn with micronutrients in albumin glycation.

  14. The receptor for advanced glycation end products (RAGE) and the lung.

    LENUS (Irish Health Repository)

    Buckley, Stephen T

    2010-01-01

    The receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin superfamily of cell surface molecules. As a pattern-recognition receptor capable of binding a diverse range of ligands, it is typically expressed at low levels under normal physiological conditions in the majority of tissues. In contrast, the lung exhibits high basal level expression of RAGE localised primarily in alveolar type I (ATI) cells, suggesting a potentially important role for the receptor in maintaining lung homeostasis. Indeed, disruption of RAGE levels has been implicated in the pathogenesis of a variety of pulmonary disorders including cancer and fibrosis. Furthermore, its soluble isoforms, sRAGE, which act as decoy receptors, have been shown to be a useful marker of ATI cell injury. Whilst RAGE undoubtedly plays an important role in the biology of the lung, it remains unclear as to the exact nature of this contribution under both physiological and pathological conditions.

  15. The receptor for advanced glycation end products (RAGE) specifically recognizes methylglyoxal-derived AGEs.

    Science.gov (United States)

    Xue, Jing; Ray, Rashmi; Singer, David; Böhme, David; Burz, David S; Rai, Vivek; Hoffmann, Ralf; Shekhtman, Alexander

    2014-05-27

    Diabetes-induced hyperglycemia increases the extracellular concentration of methylglyoxal. Methylglyoxal-derived hydroimidazolones (MG-H) form advanced glycation end products (AGEs) that accumulate in the serum of diabetic patients. The binding of hydroimidozolones to the receptor for AGEs (RAGE) results in long-term complications of diabetes typified by vascular and neuronal injury. Here we show that binding of methylglyoxal-modified albumin to RAGE results in signal transduction. Chemically synthesized peptides containing hydroimidozolones bind specifically to the V domain of RAGE with nanomolar affinity. The solution structure of an MG-H1-V domain complex revealed that the hydroimidazolone moiety forms multiple contacts with a positively charged surface on the V domain. The high affinity and specificity of hydroimidozolones binding to the V domain of RAGE suggest that they are the primary AGE structures that give rise to AGEs-RAGE pathologies.

  16. Receptor for Advanced Glycation End Products (RAGE) Deficiency Attenuates the Development of Atherosclerosis in Diabetes

    Science.gov (United States)

    Soro-Paavonen, Aino; Watson, Anna M.D.; Li, Jiaze; Paavonen, Karri; Koitka, Audrey; Calkin, Anna C.; Barit, David; Coughlan, Melinda T.; Drew, Brian G.; Lancaster, Graeme I.; Thomas, Merlin; Forbes, Josephine M.; Nawroth, Peter P.; Bierhaus, Angelika; Cooper, Mark E.; Jandeleit-Dahm, Karin A.

    2008-01-01

    OBJECTIVE—Activation of the receptor for advanced glycation end products (RAGE) in diabetic vasculature is considered to be a key mediator of atherogenesis. This study examines the effects of deletion of RAGE on the development of atherosclerosis in the diabetic apoE−/− model of accelerated atherosclerosis. RESEARCH DESIGN AND METHODS—ApoE−/− and RAGE−/−/apoE−/− double knockout mice were rendered diabetic with streptozotocin and followed for 20 weeks, at which time plaque accumulation was assessed by en face analysis. RESULTS—Although diabetic apoE−/− mice showed increased plaque accumulation (14.9 ± 1.7%), diabetic RAGE−/−/apoE−/− mice had significantly reduced atherosclerotic plaque area (4.9 ± 0.4%) to levels not significantly different from control apoE−/− mice (4.3 ± 0.4%). These beneficial effects on the vasculature were associated with attenuation of leukocyte recruitment; decreased expression of proinflammatory mediators, including the nuclear factor-κB subunit p65, VCAM-1, and MCP-1; and reduced oxidative stress, as reflected by staining for nitrotyrosine and reduced expression of various NADPH oxidase subunits, gp91phox, p47phox, and rac-1. Both RAGE and RAGE ligands, including S100A8/A9, high mobility group box 1 (HMGB1), and the advanced glycation end product (AGE) carboxymethyllysine were increased in plaques from diabetic apoE−/− mice. Furthermore, the accumulation of AGEs and other ligands to RAGE was reduced in diabetic RAGE−/−/apoE−/− mice. CONCLUSIONS—This study provides evidence for RAGE playing a central role in the development of accelerated atherosclerosis associated with diabetes. These findings emphasize the potential utility of strategies targeting RAGE activation in the prevention and treatment of diabetic macrovascular complications. PMID:18511846

  17. Natural products as anti-glycation agents: possible therapeutic potential for diabetic complications.

    Science.gov (United States)

    Elosta, Abdulhakim; Ghous, Tahseen; Ahmed, Nessar

    2012-03-01

    Diabetes mellitus is characterised by hyperglycaemia, lipidaemia and oxidative stress and predisposes affected individuals to long-term complications afflicting the eyes, skin, kidneys, nerves and blood vessels. Increased protein glycation and the subsequent build-up of tissue advanced glycation endproducts (AGEs) contribute towards the pathogenesis of diabetic complications. Protein glycation is accompanied by generation of free radicals through autoxidation of glucose and glycated proteins and via interaction of AGEs with their cell surface receptors (referred to as RAGE). Glycationderived free radicals can damage proteins, lipids and nucleic acids and contribute towards oxidative stress in diabetes. There is interest in compounds with anti-glycation activity as they may offer therapeutic potential in delaying or preventing the onset of diabetic complications. Although many different compounds are under study, only a few have successfully entered clinical trials but none have yet been approved for clinical use. Whilst the search for new synthetic inhibitors of glycation continues, little attention has been paid to anti-glycation compounds from natural sources. In the last few decades the traditional system of medicine has become a topic of global interest. Various studies have indicated that dietary supplementation with combined anti-glycation and antioxidant nutrients may be a safe and simple complement to traditional therapies targeting diabetic complications. Data for forty two plants/constituents studied for anti-glycation activity is presented in this review and some commonly used medicinal plants that possess anti-glycation activity are discussed in detail including their active ingredients, mechanism of action and therapeutic potential.

  18. Glucagon-like peptide-1 suppresses advanced glycation end product-induced monocyte chemoattractant protein-1 expression in mesangial cells by reducing advanced glycation end product receptor level.

    Science.gov (United States)

    Ishibashi, Yuji; Nishino, Yuri; Matsui, Takanori; Takeuchi, Masayoshi; Yamagishi, Sho-ichi

    2011-09-01

    Advanced glycation end products (AGE) and receptor for AGE (RAGE) interaction elicits reactive oxygen species (ROS) generation and inflammatory reactions, thereby being involved in the development and progression of diabetic nephropathy. Recently, we, along with others, found that glucagon-like peptide-1 (GLP-1), one of the incretins and a gut hormone secreted from L cells in the intestine in response to food intake, could have anti-inflammatory and antithrombogenic properties in cultured endothelial cells. However, the effects of GLP-1 on renal mesangial cells are largely unknown. Therefore, to elucidate the role of GLP-1 in diabetic nephropathy, this study investigated whether and how GLP-1 blocked AGE-induced monocyte chemoattractant protein-1 expression in human cultured mesangial cells. Gene and protein expression was analyzed by quantitative real-time reverse transcription polymerase chain reactions, Western blots, and enzyme-linked immunosorbent assay. The ROS generation was measured with dihydroethidium staining. Glucagon-like peptide-1 receptor (GLP-1R) was expressed in mesangial cells. Glucagon-like peptide-1 inhibited RAGE gene expression in mesangial cells, which was blocked by small interfering RNAs raised against GLP-1R. Furthermore, GLP-1 decreased ROS generation and subsequently reduced monocyte chemoattractant protein-1 gene and protein expression in AGE-exposed mesangial cells. An analogue of cyclic adenosine monophosphate mimicked the effects of GLP-1 on mesangial cells. Our present study suggests that GLP-1 may directly act on mesangial cells via GLP-1R and that it could work as an anti-inflammatory agent against AGE by reducing RAGE expression via activation of cyclic adenosine monophosphate pathway.

  19. Higher plasma soluble Receptor for Advanced Glycation End Products (sRAGE) levels are associated with incident cardiovascular disease and all-cause mortality in type 1 diabetes

    DEFF Research Database (Denmark)

    Nin, Johanna W M; Jorsal, Anders; Ferreira, Isabel;

    2010-01-01

    To investigate the associations of plasma levels of soluble receptor for advanced glycation end products (sRAGE) with incident cardiovascular disease (CVD) and all-cause mortality in type 1 diabetes and the extent to which any such associations could be explained by endothelial and renal dysfunct......To investigate the associations of plasma levels of soluble receptor for advanced glycation end products (sRAGE) with incident cardiovascular disease (CVD) and all-cause mortality in type 1 diabetes and the extent to which any such associations could be explained by endothelial and renal...... dysfunction, low-grade inflammation, arterial stiffness, and advanced glycation end products (AGEs)....

  20. 食品中高级糖基化终产物的研究进展%Research Progress of Advanced Glycation End-products(AGEs) in Foods

    Institute of Scientific and Technical Information of China (English)

    蔡成岗; 张慧; 李赫; 陆胤; 洪昱渂

    2013-01-01

    The conception, sources, adverse effects and detection methods of advanced glycation end-products (AGEs) in foods were reviewed. AGEs originated from reactions of sugar and proteins or lipids in foods processed in high temperature, have adverse effects on disease of cardiovascular and diabetes, stimulate inflammation and aging. AGEs are composed of a diverse groups of compounds and usually analyzed by HPLC and ELISA methods for the detection of several indicator chemicals of N-carboxymethyl-lysine and etc. Analysis of AGEs compounds will be benefical for the control of food processing and food safety ensuring.%综述食品中高级糖基化终产物的概念、来源、危害和在部分食品中的检测方法。高级糖基化终产物为糖和蛋白质或脂肪反应生成,在食品中主要存在于高温加热烹制的食品,具有促进炎症、心血管疾病、糖尿病和加速衰老等有害作用,结构复杂。检测中常以羧甲基赖氨酸等为指标,采用高效液相色谱和酶联免疫的方法进行分析。高级糖基化终产物的检测分析对于食品加工工艺控制和饮食安全保障具有重要的作用。

  1. Putative model for heat shock protein 70 complexation with receptor of advanced glycation end products through fluorescence proximity assays and normal mode analyses.

    Science.gov (United States)

    Grunwald, Marcelo Sartori; Ligabue-Braun, Rodrigo; Souza, Cristiane Santos; Heimfarth, Luana; Verli, Hugo; Gelain, Daniel Pens; Moreira, José Cláudio Fonseca

    2017-01-01

    Extracellular heat shock protein 70 (HSP70) is recognized by receptors on the plasma membrane, such as Toll-like receptor 4 (TLR4), TLR2, CD14, and CD40. This leads to activation of nuclear factor-kappa B (NF-κB), release of pro-inflammatory cytokines, enhancement of the phagocytic activity of innate immune cells, and stimulation of antigen-specific responses. However, the specific characteristics of HSP70 binding are still unknown, and all HSP70 receptors have not yet been described. Putative models for HSP70 complexation to the receptor for advanced glycation endproducts (RAGEs), considering both ADP- and ATP-bound states of HSP70, were obtained through molecular docking and interaction energy calculations. This interaction was detected and visualized by a proximity fluorescence-based assay in A549 cells and further analyzed by normal mode analyses of the docking complexes. The interacting energy of the complexes showed that the most favored docking situation occurs between HSP70 ATP-bound and RAGE in its monomeric state. The fluorescence proximity assay presented a higher number of detected spots in the HSP70 ATP treatment, corroborating with the computational result. Normal-mode analyses showed no conformational deformability in the interacting interface of the complexes. Results were compared with previous findings in which oxidized HSP70 was shown to be responsible for the differential modulation of macrophage activation, which could result from a signaling pathway triggered by RAGE binding. Our data provide important insights into the characteristics of HSP70 binding and receptor interactions, as well as putative models with conserved residues on the interface area, which could be useful for future site-directed mutagenesis studies.

  2. Novel insights in the dysfunction of human blood-brain barrier after glycation.

    Science.gov (United States)

    Hussain, Maryam; Bork, Kaya; Gnanapragassam, Vinayaga S; Bennmann, Dorit; Jacobs, Kathleen; Navarette-Santos, Alexander; Hofmann, Britt; Simm, Andreas; Danker, Kerstin; Horstkorte, Rüdiger

    2016-04-01

    The blood-brain barrier (BBB) provides a dynamic and complex interface consisting of endothelial cells, pericytes and astrocytes, which are embedded in a collagen and fibronectin-rich basement membrane. This complex structure restricts the diffusion of small hydrophilic solutes and macromolecules as well as the transmigration of leukocytes into the brain. It has been shown that carbonyl stress followed by the formation of advanced glycation endproducts (AGE=glycation) interfere with the BBB integrity and function. Here, we present data that carbonyl stress induced by methylglyoxal leads to glycation of endothelial cells and the basement membrane, which interferes with the barrier-function and with the expression of RAGE, occludin and ZO-1. Furthermore, methylglyoxal induced carbonyl stress promotes the expression of the pro-inflammatory interleukins IL-6 and IL-8. In summary, this study provides new insights into the relationship between AGE formation by carbonyl stress and brain microvascular endothelial barrier dysfunction.

  3. Detection of advanced glycation end products (AGEs) on human skin by in vivo confocal Raman spectroscopy

    Science.gov (United States)

    Martin, A. A.; Pereira, L.; Ali, S. M.; Pizzol, C. D.; Tellez, C. A.; Favero, P. P.; Santos, L.; da Silva, V. V.; Praes, C. E. O.

    2016-03-01

    The aging process involves the reduction in the production of the major components of skin tissue. During intrinsic aging and photoaging processes, in dermis of human skin, fibroblasts become senescent and have decreased activity, which produce low levels of collagen. Moreover, there is accumulation of advanced glycation end products (AGEs). AGEs have incidence in the progression of age-related diseases, principally in diabetes mellitus and in Alzheimer's diseases. AGEs causes intracellular damage and/or apoptosis leading to an increase of the free radicals, generating a crosslink with skin proteins and oxidative stress. The aim of this study is to detect AGEs markers on human skin by in vivo Confocal Raman spectroscopy. Spectra were obtained by using a Rivers Diagnostic System, 785 nm laser excitation and a CCD detector from the skin surface down to 120 μm depth. We analyzed the confocal Raman spectra of the skin dermis of 30 women volunteers divided into 3 groups: 10 volunteers with diabetes mellitus type II, 65-80 years old (DEW); 10 young healthy women, 20-33 years old (HYW); and 10 elderly healthy women, 65-80 years old (HEW). Pentosidine and glucosepane were the principally identified AGEs in the hydroxyproline and proline Raman spectral region (1000-800 cm-1), in the 1.260-1.320 cm-1 region assignable to alpha-helical amide III modes, and in the Amide I region. Pentosidine and glucosepane calculated vibrational spectra were performed through Density Functional Theory using the B3LYP functional with 3-21G basis set. Difference between the Raman spectra of diabetic elderly women and healthy young women, and between healthy elderly women and healthy young women were also obtained with the purpose of identifying AGEs Raman bands markers. AGEs peaks and collagen changes have been identified and used to quantify the glycation process in human skin.

  4. Distinct associations of HbA(1c) and the urinary excretion of pentosidine, an advanced glycosylation end-product, with markers of endothelial function in insulin-dependent diabetes mellitus

    NARCIS (Netherlands)

    Smulders, R.A.; Stehouwer, C.D.A.; Schalkwijk, C.G.; Donker, A.J.M.; Hinsbergh, V.W.M. van; TeKoppele, J.M.

    1998-01-01

    Dysfunction of the vascular endothelium is considered an early step in the development of diabetic angiopathy. Hyperglycaemia results in endothelial dysfunction, both through direct effects of glucose and through formation of advanced glycosylation end-products (AGEs). We hypothesized that the effec

  5. Comparative LC-MS/MS profiling of free and protein-bound early and advanced glycation-induced lysine modifications in dairy products.

    Science.gov (United States)

    Hegele, Jörg; Buetler, Timo; Delatour, Thierry

    2008-06-01

    Free and protein-bound forms of early and advanced glycation-induced lysine (Lys) modifications were quantified in dairy products by LC-MS/MS using a stable isotope dilution assay. The glycation profiles for N(epsilon)-fructoselysine (FL), N(epsilon)-carboxymethyllysine (CML) and pyrraline (Pyr) were monitored in raw and processed cow milk to investigate whether free glycation products could serve as fast and simple markers to assess the extent of protein glycation in dairy products. In all milk samples, the fraction of free glycation adducts was predominantly composed of advanced modifications, e.g. 8.34+/-3.81 nmol CML per micromol of free Lys (Lys(free)) and 81.5+/-87.8 nmol Pyr micromol(-1) Lys(free)(-1) vs. 3.72+/-1.29 nmol FL micromol(-1) Lys(free)(-1). In contrast, the protein-bound early glycation product FL considerably outweighed the content of CML and Pyr in milk proteins of raw and processed cow milk, whereas severely heat treated milk products, e.g. condensed milk, contained a higher amount of protein-bound advanced glycation adducts. Typical values recorded for milk samples processed under mild conditions were 0.47+/-0.08 nmol FL micromol(-1) of protein-bound Lys (Lys(p-b)), 0.04+/-0.03 nmol CML micromol(-1) Lys(p-b)(-1) and 0.06+/-0.02 nmol Pyr micromol(-1)Lys(p-b)(-1). It was particularly noticeable, however, that mild heat treatment of raw milk, i.e. pasteurization and UHT treatment, did not significantly increase the amount of both free and protein-bound Lys modifications. In conclusion, the profiles of free and protein-bound glycation-induced Lys modifications were found to be different and a screening of free glycation adducts does, therefore, not allow for a conclusion about the protein glycation status of dairy products.

  6. 皮肤AGEs检测和血清AGEs测定相关性研究%Correlation between skin advanced glycation end products and serum advanced glycation end products

    Institute of Scientific and Technical Information of China (English)

    叶成松; 叶山东; 王贻坤; 张元志; 侯华毅; 汪姗

    2014-01-01

    目的:探讨2型糖尿病患者皮肤晚期糖基化终末产物(AGEs)与血清 AGEs的相关性,评估皮肤 AGEs检测的可靠性。方法2型糖尿病患者74例(糖尿病组),分别使用皮肤荧光光谱法检测皮肤 AGEs 和 ELISA法测定血清 AGEs,正常对照组33例,为同期体检健康人群。结果糖尿病组皮肤 AGEs和血清 AGEs水平明显高于正常对照组,差异有统计学意义,P<0.01;皮肤 AGEs与血清 AGEs呈显著正相关(r=0.939,P<0.01)。结论皮肤荧光光谱法测定皮肤 AGEs可反映人体体内 AGEs水平。%Objective To explore the correlation between skin advanced glycation end products(SAGEs)and serum AGEs in type 2 diabetes and evaluate the reliability of SAGEs detection.Methods 74 patients with type 2 diabetes were recruited,SAGEs were measured by using skin autofluorescence spectrometry method,serum AGEs were meas-ured by using ELISA method,33 healthy people were selected as normal control group.Results Compared with control group,the SAGEs level were obviously increased in patients with type 2 diabetes,P<0.01,and the level of serum AGEs were also increased in diabetes,P<0.01,the SAGEs and serum AGEs were significant positive correlation(r=0.939,P<0.01).Conclusion SAGEs measured by skin autofluorescence spectrometry method could be used to reflect the AGEs level in vivo.

  7. Potential Dual Role of Eugenol in Inhibiting Advanced Glycation End Products in Diabetes: Proteomic and Mechanistic Insights.

    Science.gov (United States)

    Singh, Priyanka; Jayaramaiah, Ramesha H; Agawane, Sachin B; Vannuruswamy, Garikapati; Korwar, Arvind M; Anand, Atul; Dhaygude, Vitthal S; Shaikh, Mahemud L; Joshi, Rakesh S; Boppana, Ramanamurthy; Kulkarni, Mahesh J; Thulasiram, Hirekodathakallu V; Giri, Ashok P

    2016-01-07

    Medicinally important genus Ocimum harbors a vast pool of chemically diverse metabolites. Current study aims at identifying anti-diabetic candidate compounds from Ocimum species. Major metabolites in O. kilimandscharicum, O. tenuiflorum, O. gratissimum were purified, characterized and evaluated for anti-glycation activity. In vitro inhibition of advanced glycation end products (AGEs) by eugenol was found to be highest. Preliminary biophysical analysis and blind docking studies to understand eugenol-albumin interaction indicated eugenol to possess strong binding affinity for surface exposed lysines. However, binding of eugenol to bovine serum albumin (BSA) did not result in significant change in secondary structure of protein. In vivo diabetic mice model studies with eugenol showed reduction in blood glucose levels by 38% likely due to inhibition of α-glucosidase while insulin and glycated hemoglobin levels remain unchanged. Western blotting using anti-AGE antibody and mass spectrometry detected notably fewer AGE modified peptides upon eugenol treatment both in vivo and in vitro. Histopathological examination revealed comparatively lesser lesions in eugenol-treated mice. Thus, we propose eugenol has dual mode of action in combating diabetes; it lowers blood glucose by inhibiting α-glucosidase and prevents AGE formation by binding to ε-amine group on lysine, protecting it from glycation, offering potential use in diabetic management.

  8. Ability of resveratrol to inhibit advanced glycation end product formation and carbohydrate-hydrolyzing enzyme activity, and to conjugate methylglyoxal.

    Science.gov (United States)

    Shen, Yixiao; Xu, Zhimin; Sheng, Zhanwu

    2017-02-01

    Glycation can generate advanced glycation end products (AGE) and its intermediates methylglyoxal (MGO) and glyoxal in foods, which increase the risk of developing diabetes diseases. In this study, the effect of resveratrol against AGE formation, carbohydrate-hydrolyzing enzyme activity and trapping MGO capability were evaluated. Resveratrol showed a significant inhibition capability against AGE formation in bovine serum albumin (BSA)-fructose, BSA-MGO and arginine-MGO models with inhibition percentages of 57.94, 85.95 and 99.35%, respectively. Furthermore, resveratrol acted as a competitive inhibitor for α-amylase with IC50 3.62μg/ml, while it behaved in an uncompetitive manner for α-glucosidase with an IC50 of 17.54μg/l. A prevention of BSA protein glycation was observed in the BSA-fructose model with addition of resveratrol. Three types of resveratrol-MGO adducts were identified in the model consisting of MGO and resveratrol. The results demonstrated that resveratrol has potential in reducing glycation in foods and retarding carbohydrate-hydrolyzing enzyme activities.

  9. The impact of salsalate treatment on serum levels of advanced glycation end products in type 2 diabetes.

    Science.gov (United States)

    Barzilay, Joshua I; Jablonski, Kathleen A; Fonseca, Vivian; Shoelson, Steven E; Goldfine, Allison B; Strauch, Christopher; Monnier, Vincent M

    2014-04-01

    OBJECTIVE Salsalate is a nonacetylated salicylate that lowers glucose levels in people with type 2 diabetes (T2D). Here we examined whether salsalate also lowered serum-protein-bound levels of early and advanced glycation end products (AGEs) that have been implicated in diabetic vascular complications. RESEARCH DESIGN AND METHODS Participants were from the Targeting Inflammation Using Salsalate for Type 2 Diabetes (TINSAL-T2D) study, which examined the impact of salsalate treatment on hemoglobin A1c (HbA1c) and a wide variety of other parameters. One hundred eighteen participants received salsalate, 3.5 g/day for 48 weeks, and 109 received placebo. Early glycation product levels (HbA1c and fructoselysine [measured as furosine]) and AGE levels (glyoxal and methylglyoxal hydroimidazolones [G-(1)H, MG-(1)H], carboxymethyllysine [CML], carboxyethyllysine [CEL], pentosidine) were measured in patient serum samples. RESULTS Forty-eight weeks of salsalate treatment lowered levels of HbA1c and serum furosine (P glycation factors. Pentosidine level changes were unrelated to changes in levels of renal function, inflammation, or cytokines. CONCLUSIONS Salsalate therapy was associated with a reduction in early but not late glycation end products. There was a paradoxical increase in serum pentosidine levels suggestive of an increase in oxidative stress or decreased clearance of pentosidine precursor.

  10. Biologic variability in plasma glucose, hemoglobin A1c, and advanced glycation end products associated with diabetes complications.

    Science.gov (United States)

    Leslie, R David G; Cohen, Robert M

    2009-07-01

    Plasma glucose plays a key role in the complications of diabetes mellitus. Hemoglobin A1c (HbA1c) and circulating concentrations of advanced glycation end products (AGEs) are central to diabetes clinical care and pathophysiology. However, there is evidence for variation between individuals in the relationship of plasma glucose to both these measures and to specific complications. The glycation gap (GG) and hemoglobin glycation index represent tools for quantitating the variability in the relationship between plasma glucose and HbA1c useful for identification of underlying mechanisms. Recent evidence demonstrates the heritability of HbA1c, the GG, and AGEs, yet not of glycated serum proteins. There has been tremendous effort devoted to identifying the heritable basis of types 1 and 2 diabetes; however, studies on the heritable contributors to these mediators of glucose effect on complications are only beginning. New evidence for normal biologic variation in the distribution of glucose into the red blood cell (RBC) intracellular compartment and RBC lifespan in people with and without diabetes represent candidates for heritable mechanisms and contributors to the rise in HbA1c with age. Taken as a whole, genetic and mechanistic evidence suggests new potential targets for complications prevention and improvement in complications risk estimation. These observations could help tilt the risk-benefit balance in glycemic control toward a more beneficial outcome.

  11. Receptor for advanced glycation end products Glycine 82 Serine polymorphism and risk of cardiovascular events in rheumatoid arthritis

    OpenAIRE

    Carroll, Lisa; Frazer, Ian H; Turner, Malcolm; Marwick, Thomas H.; Thomas, Ranjeny

    2007-01-01

    Patients with rheumatoid arthritis (RA) are at risk of excess mortality, predominantly owing to cardiovascular (CV) events. The receptor for advanced glycation end products (RAGE) has been implicated in the perpetuation of the chronic inflammatory response in vascular disease. A Gly82→Ser polymorphism in the RAGE gene, which is associated with enhanced RAGE signaling, is present more frequently in patients with RA than the general population. To investigate whether RAGE Gly82→Ser polymorphism...

  12. Serum soluble receptor for advanced glycation end products correlates inversely with measures of adiposity in young adults.

    Science.gov (United States)

    Davis, Kathleen E; Prasad, Chandan; Vijayagopal, Parakat; Juma, Shanil; Imrhan, Victorine

    2014-06-01

    Advanced glycation end products (AGEs) may promote inflammation by interacting with the receptor for advanced glycation end products. Serum soluble receptor for advanced glycation end products (sRAGE), a form of receptor for advanced glycation end products thought to mediate AGE's inflammatory properties, is decreased in diabetes mellitus and coronary artery disease. Evidence in older adults suggests that sRAGE is depressed in individuals without current disease who are obese; however, 2 studies have failed to find this correlation. We hypothesized that sRAGE would be inversely correlated with adiposity and positively correlated with inflammation, even in apparently healthy, young adults. By considering adults of body mass index (BMI) varying from normal weight to overweight and obese, we aimed to define how closely AGEs and sRAGE correlate with adiposity and other indicators of metabolic stress. Anthropometric measurements and fasting blood samples were obtained from participants (n = 69). Sera were analyzed for sRAGE, n-epsilon carboxy-methyl-lysine, a measure of AGEs, and high sensitivity C-reactive protein. High molecular weight adiponectin, glucose, insulin, total cholesterol, high-density lipoprotein, and triacylglycerol were also assessed (n = 32). Spearman rank correlations were used to evaluate the relationship among indicators of adiposity and biochemical indicators of metabolic health and inflammation. Factors inversely correlated with sRAGE include weight (Rs = -0.397; P = .001), waist circumference (-0.291; P = .015), and BMI (-0.3338; P = .004). High molecular weight adiponectin was positively correlated with sRAGE, and predictors of sRAGE included BMI and total cholesterol. This is the first time these associations have been found in a diverse population of young adults.

  13. Inhibition of glucose-and fructose-mediated protein glycation by infusions and ethanolic extracts of ten culinary herbs and spices

    Institute of Scientific and Technical Information of China (English)

    Jugjeet Singh Ramkissoon; Mohamad Fawzi Mahomoodally; Anwar Hussein Subratty; Nessar Ahmed

    2016-01-01

    Objective: To investigate the inhibitory activity of ten culinary herbs and spices namely on glucose-mediated glycation(GMG) and fructose-mediated glycation(FMG) of bovine serum albumin.Methods: Fluorescence was used as an index of albumin glycation using glucose and fructose as substrates in the presence of infusions and ethanolic extracts of ten culinary herbs and spices. Antioxidant activity of the extracts was evaluated using reducing power,metal ion chelating and superoxide radical scavenging assays. Phytochemicals profile was analysed using 13 standard methods.Results: FMG was found to be significantly higher than GMG(95 and 84 AU,respectively; P 0.05) was found in the percentage glycation inhibitory activity of infusions compared to ethanolic extracts. The mean percentage inhibitory activity of the extracts for GMG(45.9%) and for FMG(45.1%) was not significantly different(P > 0.05). Qualitative phytochemical analysis showed the presence of alkaloids, flavonoids, tannins, terpenoids, anthraquinones, steroids, reducing sugars, proteins, phenols,saponins, phlobatannins, and cardiac glycosides.Conclusions: The higher rate of fluorescence generation by fructation suggests that glycation by fructose deserves much attention as a glycating agent. Data herein showed that the extracts inhibited GMG and FMG. Thus, these edible plants could be a natural source of antioxidants and anti-glycation agent for preventing advanced glycation endproducts-mediated complications.

  14. Advanced Glycation End Products: Link between Diet and Ovulatory Dysfunction in PCOS?

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    Deepika Garg

    2015-12-01

    Full Text Available PCOS is the most common cause of anovulation in reproductive-aged women with 70% experiencing ovulatory problems. Advanced glycation end products are highly reactive molecules that are formed by non-enzymatic reactions of sugars with proteins, nucleic acids and lipids. AGEs are also present in a variety of diet where substantial increase in AGEs can result due to thermal processing and modifications of food. Elevation in bodily AGEs, produced endogenously or absorbed exogenously from high-AGE diets, is further exaggerated in women with PCOS and is associated with ovulatory dysfunction. Additionally, increased expression of AGEs as pro-inflammatory receptors in the ovarian tissue has been observed in women with PCOS. In this review, we summarize the role of dietary AGEs as mediators of metabolic and reproductive alterations in PCOS. Once a mechanistic understanding of the relationship between AGEs and anovulation is established, there is a promise that such knowledge will contribute to the subsequent development of targeted pharmacological therapies that will treat anovulation and improve ovarian health in women with PCOS.

  15. Advanced glycation end products: A link between metabolic and endothelial dysfunction in polycystic ovary syndrome?

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    Pertynska-Marczewska, Magdalena; Diamanti-Kandarakis, Evanthia; Zhang, John; Merhi, Zaher

    2015-11-01

    Polycystic ovary syndrome (PCOS), a heterogeneous syndrome of reproductive and metabolic alterations, is associated with increased long-term risk of cardiovascular complications. This phenomenon has been linked to an increase in oxidative stress and inflammatory markers. Advanced glycation end products (AGEs) are pro-inflammatory molecules that trigger a state of intracellular oxidative stress and inflammation after binding to their cell membrane receptors RAGE. The activation of the AGE-RAGE axis has been well known to play a role in atherosclerosis in both men and women. Women with PCOS have systemic chronic inflammatory condition even at the ovarian level as represented by elevated levels of serum/ovarian AGEs and increased expression of the pro-inflammatory RAGE in ovarian tissue. Data also showed the presence of sRAGE in the follicular fluid and its potential protective role against the harmful effect of AGEs on ovarian function. Thus, whether AGE-RAGE axis constitutes a link between metabolic and endothelial dysfunction in women with PCOS is addressed in this review. Additionally, we discuss the role of hormonal changes observed in PCOS and how they are linked with the AGE-RAGE axis in order to better understand the nature of this complex syndrome whose consequences extend well beyond reproduction.

  16. Receptor for Advanced Glycation End Products and Its Involvement in Inflammatory Diseases

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    Yaw Kuang Chuah

    2013-01-01

    Full Text Available The receptor for advanced glycation end products (RAGE is a transmembrane receptor of the immunoglobulin superfamily, capable of binding a broad repertoire of ligands. RAGE-ligands interaction induces a series of signal transduction cascades and lead to the activation of transcription factor NF-κB as well as increased expression of cytokines, chemokines, and adhesion molecules. These effects endow RAGE with the role in the signal transduction from pathogen substrates to cell activation during the onset and perpetuation of inflammation. RAGE signaling and downstream pathways have been implicated in a wide spectrum of inflammatory-related pathologic conditions such as arteriosclerosis, Alzheimer's disease, arthritis, acute respiratory failure, and sepsis. Despite the significant progress in other RAGE studies, the functional importance of the receptor in clinical situations and inflammatory diseases still remains to be fully realized. In this review, we will summarize current understandings and lines of evidence on the molecular mechanisms through which RAGE signaling contributes to the pathogenesis of the aforementioned inflammation-associated conditions.

  17. Assessment of advanced glycated end product accumulation in skin using auto fluorescence multispectral imaging.

    Science.gov (United States)

    Larsson, Marcus; Favilla, Riccardo; Strömberg, Tomas

    2016-04-12

    Several studies have shown that advanced glycation end products (AGE) play a role in both the microvascular and macrovascular complications of diabetes and are closely linked to inflammation and atherosclerosis. AGEs accumulate in skin and can be detected using their auto fluorescence (AF). A significant correlation exists between AGE AF and the levels of AGEs as obtained from skin biopsies. A commercial device, the AGE Reader, has become available to assess skin AF for clinical purposes but, while displaying promising results, it is limited to single-point measurements performed in contact to skin tissue. Furthermore, in vivo imaging of AGE accumulation is virtually unexplored. We proposed a non-invasive, contact-less novel technique for quantifying fluorescent AGE deposits in skin tissue using a multispectral imaging camera setup (MSI) during ultraviolet (UV) exposure. Imaging involved applying a region-of-interest mask, avoiding specular reflections and a simple calibration. Results of a study conducted on 16 subjects with skin types ranging from fair to deeply pigmented skin, showed that AGE measured with MSI in forearm skin was significantly correlated with the AGE reference method (AGE Reader on forearm skin, R=0.68, p=0.005). AGE measured in facial skin was borderline significantly related to AGE Reader on forearm skin (R=0.47, p=0.078). These results support the use of the technique in devices for non-touch measurement of AGE content in either facial or forearm skin tissue over time.

  18. Age-Related Effects of Advanced Glycation End Products (Ages) in Bone Matrix on Osteoclastic Resorption.

    Science.gov (United States)

    Yang, Xiao; Gandhi, Chintan; Rahman, Md Mizanur; Appleford, Mark; Sun, Lian-Wen; Wang, Xiaodu

    2015-12-01

    Advanced glycation end products (AGEs) accumulate in bone extracellular matrix as people age. Previous studies have shown controversial results regarding the role of in situ AGEs accumulation in osteoclastic resorption. To address this issue, this study cultured human osteoclast cells directly on human cadaveric bone slices from different age groups (young and elderly) to warrant its relevance to in vivo conditions. The cell culture was terminated on the 3rd, 7th, and 10th day, respectively, to assess temporal changes in the number of differentiated osteoclasts, the number and size of osteoclastic resorption pits, the amount of bone resorbed, as well as the amount of matrix AGEs released in the medium by resorption. In addition, the in situ concentration of matrix AGEs at each resorption pit was also estimated based on its AGEs autofluorescent intensity. The results indicated that (1) osteoclastic resorption activities were significantly correlated with the donor age, showing larger but shallower resorption pits on the elderly bone substrates than on the younger ones; (2) osteoclast resorption activities were not significantly dependent on the in situ AGEs concentration in bone matrix, and (3) a correlation was observed between osteoclast activities and the concentration of AGEs released by the resorption. These results suggest that osteoclasts tend to migrate away from initial anchoring sites on elderly bone substrate during resorption compared to younger bone substrates. However, such behavior is not directly related to the in situ concentration of AGEs in bone matrix at the resorption sites.

  19. Sesamin Ameliorates Advanced Glycation End Products-Induced Pancreatic β-Cell Dysfunction and Apoptosis

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    Xiang Kong

    2015-06-01

    Full Text Available Advanced glycation end products (AGEs, the direct modulators of β-cells, have been shown to cause insulin-producing β-cell dysfunction and apoptosis through increase of intracellular reactive oxygen species (ROS production. Sesamin has been demonstrated to possess antioxidative activity. This study was designed to investigate whether sesamin protects against AGEs-evoked β-cell damage via its antioxidant property. The effects of sesamin were examined in C57BL/6J mice and MIN6 cell line. In in vivo studies, mice were intraperitoneally injected with AGEs (120 mg/kg and orally treated with sesamin (160 mg/kg for four weeks. Intraperitoneal glucose tolerance and insulin releasing tests were performed. Insulin content, ROS generation and β-cell apoptosis in pancreatic islets were also measured. In in vitro studies, MIN6 cells were pretreated with sesamin (50 or 100 μM and then exposed to AGEs (200 mg/L for 24 h. Insulin secretion, β-cell death, ROS production as well as expression and activity of NADPH oxidase were determined. Sesamin treatment obviously ameliorated AGE-induced β-cell dysfunction and apoptosis both in vivo and in vitro. These effects were associated with decreased ROS production, down-regulated expression of p67phox and p22phox, and reduced NADPH oxidase activity. These results suggest that sesamin protects β-cells from damage caused by AGEs through suppressing NADPH oxidase-mediated oxidative stress.

  20. Sesamin Ameliorates Advanced Glycation End Products-Induced Pancreatic β-Cell Dysfunction and Apoptosis.

    Science.gov (United States)

    Kong, Xiang; Wang, Guo-Dong; Ma, Ming-Zhe; Deng, Ru-Yuan; Guo, Li-Qun; Zhang, Jun-Xiu; Yang, Jie-Ren; Su, Qing

    2015-06-09

    Advanced glycation end products (AGEs), the direct modulators of β-cells, have been shown to cause insulin-producing β-cell dysfunction and apoptosis through increase of intracellular reactive oxygen species (ROS) production. Sesamin has been demonstrated to possess antioxidative activity. This study was designed to investigate whether sesamin protects against AGEs-evoked β-cell damage via its antioxidant property. The effects of sesamin were examined in C57BL/6J mice and MIN6 cell line. In in vivo studies, mice were intraperitoneally injected with AGEs (120 mg/kg) and orally treated with sesamin (160 mg/kg) for four weeks. Intraperitoneal glucose tolerance and insulin releasing tests were performed. Insulin content, ROS generation and β-cell apoptosis in pancreatic islets were also measured. In in vitro studies, MIN6 cells were pretreated with sesamin (50 or 100 μM) and then exposed to AGEs (200 mg/L) for 24 h. Insulin secretion, β-cell death, ROS production as well as expression and activity of NADPH oxidase were determined. Sesamin treatment obviously ameliorated AGE-induced β-cell dysfunction and apoptosis both in vivo and in vitro. These effects were associated with decreased ROS production, down-regulated expression of p67(phox) and p22(phox), and reduced NADPH oxidase activity. These results suggest that sesamin protects β-cells from damage caused by AGEs through suppressing NADPH oxidase-mediated oxidative stress.

  1. Blockade of PKC-beta protects HUVEC from advanced glycation end products induced inflammation.

    Science.gov (United States)

    Xu, Youhua; Wang, Shanshan; Feng, Liang; Zhu, Quan; Xiang, Ping; He, Bao

    2010-12-01

    Advanced glycation end products (AGEs) have been recognized as a pivotal inducer in diabetes and kinds of aging-related vasculopathy. Endothelial dysfunction and inflammatory cells adhesion to endothelium have been regarded as important and early factors in the pathogenesis of vascular complications in diabetic patients. Owing to the key role of PKC-beta in AGEs-induced vascular dysfunction, we investigated effects of blocking PKC-beta by LY333531 on macrophage adhesion to HUVEC and the related mechanism. Transwell HUVEC-macrophage co-culture system was established to evaluate macrophage migration and adhesion ability. Immunocytochemistry was applied to examine TGF-beta1, ICAM-1 and RAGE protein expressions by SABC or SABC-AP method; mRNA expression of TGF-beta1, ICAM-1 and RAGE was determined by real-time RT-PCR. SOD and MDA levels in culture supernatant were detected. We found that LY333531 significantly reduced AGEs-induced macrophage adhesion to HUVEC. Blockade of PKC-beta strikingly decreased HUVEC TGF-beta1 and ICAM-1 expression in both protein and mRNA levels, RAGE protein level was also down-regulated. Furthermore, the anti-oxidative stress index, SOD/MDA was dramatically elevated on LY333531 application. Therefore we conclude that LY333531 can reduce AGEs-induced macrophage adhesion to endothelial cells and relieve the local inflammation, this was realized by its effect on decreasing inflammatory cytokines' expression and increasing cell anti-oxidative ability.

  2. Receptor for Advanced Glycation End Products (RAGE) Serves a Protective Role during Klebsiella pneumoniae - Induced Pneumonia.

    Science.gov (United States)

    Achouiti, Ahmed; de Vos, Alex F; van 't Veer, Cornelis; Florquin, Sandrine; Tanck, Michael W; Nawroth, Peter P; Bierhaus, Angelika; van der Poll, Tom; van Zoelen, Marieke A D

    2016-01-01

    Klebsiella species is the second most commonly isolated gram-negative organism in sepsis and a frequent causative pathogen in pneumonia. The receptor for advanced glycation end products (RAGE) is expressed on different cell types and plays a key role in diverse inflammatory responses. We here aimed to investigate the role of RAGE in the host response to Klebsiella (K.) pneumoniae pneumonia and intransally inoculated rage gene deficient (RAGE-/-) and normal wild-type (Wt) mice with K. pneumoniae. Klebsiella pneumonia resulted in an increased pulmonary expression of RAGE. Furthermore, the high-affinity RAGE ligand high mobility group box-1 was upregulated during K. pneumoniae pneumonia. RAGE deficiency impaired host defense as reflected by a worsened survival, increased bacterial outgrowth and dissemination in RAGE-/- mice. RAGE-/- neutrophils showed a diminished phagocytosing capacity of live K. pneumoniae in vitro. Relative to Wt mice, RAGE-/- mice demonstrated similar lung inflammation, and slightly elevated-if any-cytokine and chemokine levels and unchanged hepatocellular injury. In addition, RAGE-/- mice displayed an unaltered response to intranasally instilled Klebsiella lipopolysaccharide (LPS) with respect to pulmonary cell recruitment and local release of cytokines and chemokines. These data suggest that (endogenous) RAGE protects against K. pneumoniae pneumonia. Also, they demonstrate that RAGE contributes to an effective antibacterial defense during K. pneumoniae pneumonia, at least partly via its participation in the phagocytic properties of professional granulocytes. Additionally, our results indicate that RAGE is not essential for the induction of a local and systemic inflammatory response to either intact Klebsiella or Klebsiella LPS.

  3. Advanced glycation end products (AGEs) and their receptor (RAGE) induce apoptosis of periodontal ligament fibroblasts

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    Li, D.X.; Deng, T.Z.; Lv, J.; Ke, J. [Department of Stomatology, Air Force General Hospital PLA, Haidian District, Beijing (China)

    2014-09-19

    Diabetics have an increased prevalence of periodontitis, and diabetes is one of the causative factors of severe periodontitis. Apoptosis is thought to be involved in this pathogenic relationship. The aim of this study was to investigate apoptosis in human periodontal ligament (PDL) fibroblasts induced by advanced glycation end products (AGEs) and their receptor (RAGE). We examined the roles of apoptosis, AGEs, and RAGE during periodontitis in diabetes mellitus using cultured PDL fibroblasts that were treated by AGE-modified bovine serum albumin (AGE-BSA), bovine serum albumin (BSA) alone, or given no treatment (control). Microscopy and real-time quantitative PCR indicated that PDL fibroblasts treated with AGE-BSA were deformed and expressed higher levels of RAGE and caspase 3. Cell viability assays and flow cytometry indicated that AGE-BSA reduced cell viability (69.80±5.50%, P<0.01) and increased apoptosis (11.31±1.73%, P<0.05). Hoechst 33258 staining and terminal-deoxynucleotidyl transferase-mediated nick-end labeling revealed that AGE-BSA significantly increased apoptosis of PDL fibroblasts. The results showed that the changes in PDL fibroblasts induced by AGE-BSA may explain how AGE-RAGE participates in and exacerbates periodontium destruction.

  4. Advanced glycation end products (AGEs and their receptor (RAGE induce apoptosis of periodontal ligament fibroblasts

    Directory of Open Access Journals (Sweden)

    D.X. Li

    2014-12-01

    Full Text Available Diabetics have an increased prevalence of periodontitis, and diabetes is one of the causative factors of severe periodontitis. Apoptosis is thought to be involved in this pathogenic relationship. The aim of this study was to investigate apoptosis in human periodontal ligament (PDL fibroblasts induced by advanced glycation end products (AGEs and their receptor (RAGE. We examined the roles of apoptosis, AGEs, and RAGE during periodontitis in diabetes mellitus using cultured PDL fibroblasts that were treated by AGE-modified bovine serum albumin (AGE-BSA, bovine serum albumin (BSA alone, or given no treatment (control. Microscopy and real-time quantitative PCR indicated that PDL fibroblasts treated with AGE-BSA were deformed and expressed higher levels of RAGE and caspase 3. Cell viability assays and flow cytometry indicated that AGE-BSA reduced cell viability (69.80±5.50%, P<0.01 and increased apoptosis (11.31±1.73%, P<0.05. Hoechst 33258 staining and terminal-deoxynucleotidyl transferase-mediated nick-end labeling revealed that AGE-BSA significantly increased apoptosis of PDL fibroblasts. The results showed that the changes in PDL fibroblasts induced by AGE-BSA may explain how AGE-RAGE participates in and exacerbates periodontium destruction.

  5. Advanced glycation end products: a link between periodontitis and diabetes mellitus?

    Science.gov (United States)

    Gurav, Abhijit N

    2013-09-01

    Advanced glycation end products (AGEs) are synthesized via the non enzymaticglycation and oxidation of proteins, lipids and nucleic acids. The production of AGEs is particularly enhanced in chronic hyperglycemia, as in diabetes mellitus (DM). The formation of irreversible AGEs affects the tissues by compromising the physiologic and mechanical functions, as a result of defective constitution of the extracellular matrix (ECM) components. Periodontitis is an inflammatory disease of microbial origin, resulting in devastation of the tooth supporting apparatus. This disease condition has severe implicationsin subjects with DM, since the tooth supporting tissuescontain ECM targeted by AGE. There is miniscule literature regarding the contribution of AGE to periodontal disease in patients with DM. The purpose of this review is to address the prejudicial role of AGEs in relation to various tissue components. This paper is an attempt to elucidatethe possible link of AGEs between periodontitis and DM. The exploration of novel therapeutic strategies to target AGEs for the treatment of periodontitis in DM subjects is certainly intriguing.

  6. Protection effect of endomorphins on advanced glycation end products induced injury in endothelial cells.

    Science.gov (United States)

    Liu, Jing; Yan, Liping; Niu, Ruilan; Tian, Limin; Zhang, Qi; Quan, Jinxing; Liu, Hua; Wei, Suhong; Guo, Qian

    2013-01-01

    Endomorphins (EMs) have a very important bridge-function in cardiovascular, endocrinological, and neurological systems. This study is to investigate the effects of EMs on the synthesis and secretion of vasoactive substances induced by advanced glycation end products in primary cultured human umbilical vein endothelial cells (HUVECs). Firstly, HUVECs were stimulated with AGEs-bovine serum albumin (AGEs-BSA), bovine serum albumin (BSA), or both AGEs-BSA and EMs together, respectively. Then, HUVEC survival rate was calculated by MTT assay, the levels of NO, endothelial nitric oxide synthase (eNOS), and inducible nitric oxide synthase (iNOS) were detected by colorimetric analysis, and the contents of endothelin-1 (ET-1) were detected by ELISA. The mRNA levels of eNOS and ET-1 were measured by RT-PCR. The expression of p38 mitogen-activated protein kinase (p38 MAPK) was detected by immunofluorescence assay. The results showed that the mRNA expression and secretion of eNOS were significantly enhanced after incubation with EMs compared to those with AGEs-BSA, while the secretion of NO and iNOS, mRNA expression, and secretion of ET-1 had opposite changes. The fluorescence intensity of p38MAPK in nuclear was decreased after pretreatment with EMs compared to incubation with AGEs-BSA. Conclusion. The present study suggests that EMs have certain protection effect on AGEs-BSA-induced injury in HUVEC.

  7. Short-term effects of dietary advanced glycation end products in rats.

    Science.gov (United States)

    Poulsen, Malene W; Andersen, Jeanette M; Hedegaard, Rikke V; Madsen, Andreas N; Krath, Britta N; Monošík, Rastislav; Bak, Monika J; Nielsen, John; Holst, Birgitte; Skibsted, Leif H; Larsen, Lesli H; Dragsted, Lars O

    2016-02-28

    Dietary advanced glycation end products (AGE) formed during heating of food have gained interest as potential nutritional toxins with adverse effects on inflammation and glucose metabolism. In the present study, we investigated the short-term effects of high and low molecular weight (HMW and LMW) dietary AGE on insulin sensitivity, expression of the receptor for AGE (RAGE), the AGE receptor 1 (AGER1) and TNF-α, F2-isoprostaglandins, body composition and food intake. For 2 weeks, thirty-six Sprague-Dawley rats were fed a diet containing 20% milk powder with different proportions of this being given as heated milk powder (0, 40 or 100%), either native (HMW) or hydrolysed (LMW). Gene expression of RAGE and AGER1 in whole blood increased in the group receiving a high AGE LMW diet, which also had the highest urinary excretion of the AGE, methylglyoxal-derived hydroimidazolone 1 (MG-H1). Urinary excretion of N ε-carboxymethyl-lysine increased with increasing proportion of heat-treated milk powder in the HMW and LMW diets but was unrelated to gene expression. There was no difference in insulin sensitivity, F2-isoprostaglandins, food intake, water intake, body weight or body composition between the groups. In conclusion, RAGE and AGER1 expression can be influenced by a high AGE diet after only 2 weeks in proportion to MG-H1 excretion. No other short-term effects were observed.

  8. Receptor for advanced glycation end products is detrimental during influenza A virus pneumonia.

    Science.gov (United States)

    van Zoelen, Marieke A D; van der Sluijs, Koenraad F; Achouiti, Ahmed; Florquin, Sandrine; Braun-Pater, Jennie M; Yang, Huan; Nawroth, Peter P; Tracey, Kevin J; Bierhaus, Angelika; van der Poll, Tom

    2009-09-01

    Pneumonia caused by influenza A virus (IAV) can have devastating effects, resulting in respiratory failure and death. The idea that a new influenza pandemic might occur in the near future has triggered renewed interests in IAV infection. The receptor for advanced glycation end products (RAGE) is expressed on different cell types and plays a key role in diverse inflammatory processes. We here investigated the role of RAGE in the host response to IAV pneumonia using wild-type (wt) and RAGE deficient ((-/-)) mice. Whereas strong RAGE was constitutively expressed in the lungs of uninfected wt mice, in particular on endothelium, IAV pneumonia was associated with enhanced expression on endothelium and de novo expression on bronchial epithelium. Additionally, the high-affinity RAGE ligand high mobility group box 1 was upregulated during IAV pneumonia. RAGE(-/-) mice were relatively protected from IAV induced mortality and showed an improved viral clearance and enhanced cellular T cell response and activation of neutrophils. These data suggest that RAGE is detrimental during IAV pneumonia.

  9. Advanced glycation end products (AGEs) and their receptor (RAGE) induce apoptosis of periodontal ligament fibroblasts.

    Science.gov (United States)

    Li, D X; Deng, T Z; Lv, J; Ke, J

    2014-12-01

    Diabetics have an increased prevalence of periodontitis, and diabetes is one of the causative factors of severe periodontitis. Apoptosis is thought to be involved in this pathogenic relationship. The aim of this study was to investigate apoptosis in human periodontal ligament (PDL) fibroblasts induced by advanced glycation end products (AGEs) and their receptor (RAGE). We examined the roles of apoptosis, AGEs, and RAGE during periodontitis in diabetes mellitus using cultured PDL fibroblasts that were treated by AGE-modified bovine serum albumin (AGE-BSA), bovine serum albumin (BSA) alone, or given no treatment (control). Microscopy and real-time quantitative PCR indicated that PDL fibroblasts treated with AGE-BSA were deformed and expressed higher levels of RAGE and caspase 3. Cell viability assays and flow cytometry indicated that AGE-BSA reduced cell viability (69.80 ± 5.50%, PAGE-BSA significantly increased apoptosis of PDL fibroblasts. The results showed that the changes in PDL fibroblasts induced by AGE-BSA may explain how AGE-RAGE participates in and exacerbates periodontium destruction.

  10. The Role of Receptor for Advanced Glycation End Products (RAGE in the Proliferation of Hepatocellular Carcinoma

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    Wei Tian

    2012-05-01

    Full Text Available The receptor for advanced glycation end products (RAGE is oncogenic and overexpressed in human cancers, but its role in hepatocellular carcinoma remains unclear. Here we demonstrated that RAGE is overexpressed in primary hepatocellular carcinoma (PHC compared to adjacent para-neoplastic liver samples. Serum endogenous secretory RAGE levels were also increased in PHC patients (p < 0.01. Moreover, we demonstrated that RAGE regulates cellular proliferation in Hepatocellular carcinoma (HCC. Knockdown of RAGE by specific siRNA inhibited cellular growth in the hepatocellular carcinoma cell line, Huh7, whereas the RAGE ligand, high mobility group box 1 protein (HMGB1 increased cellular proliferation. In addition, knockdown of RAGE by siRNA arrested cells in the G1 phase and inhibited DNA synthesis (p < 0.01, while HMGB1 protein decreased the number of cells in the G1 phase and increased the number in the S phase (p < 0.05. Furthermore, quantitative real time RT-PCR (qRT-PCR and Western Blot results demonstrated that RAGE and HMGB1 positively regulate NF-κB p65 expression in Huh7 cells. These studies suggest that RAGE and RAGE ligands are important targets for therapeutic intervention in hepatocellular carcinoma.

  11. Inhibition of fluorescent advanced glycation end products (AGEs) of human serum albumin upon incubation with 3-β-hydroxybutyrate.

    Science.gov (United States)

    Bohlooli, M; Moosavi-Movahedi, A A; Taghavi, F; Saboury, A A; Maghami, P; Seyedarabi, A; Moosavi-Movahedi, F; Ahmad, F; Shockravi, A; Habibi-Rezaei, M

    2014-06-01

    Advanced glycation end products (AGEs), which are the final products of glycation, have a major role in diabetic complication and neurodegenerative disorders. The 3-β-hydroxybutyrate (3BHB), a ketone body which is produced by the liver, can be detected in increased concentrations in individuals post fasting and prolonged exercises and in diabetic (type I) patients. In this study, the inhibitory effect of 3BHB on AGEs formation by glucose from the human serum albumin (HSA) was studied at physiological conditions after 35 days of incubation, using physical techniques such as circular dichroism and fluorescence spectroscopy, as well as differential scanning calorimetry (DSC). The fluorescence intensity measurements of glycated HSA by glucose (GHSA) in the presence of 3BHB indicate a decrease in AGEs formation. The DSC deconvolution profile results also confirm the protective role of 3BHB on incubated with glucose by preventing the enthalpy reduction of the HSA tail segment, compared with the deconvolution profile seen for incubated with glucose alone. The concentration of 3BHB used in this study is in accordance with the concentration detected in the body of individuals post fasting and prolonged exercises.

  12. Advanced glycation end products, oxidative stress and metalloproteinases are altered in the cerebral microvasculature during aging.

    Science.gov (United States)

    Safciuc, Florentina; Constantin, Alina; Manea, Adrian; Nicolae, Manuela; Popov, Doina; Raicu, Monica; Alexandru, Dorin; Constantinescu, Elena

    2007-11-01

    Biological aging is associated with an increased incidence of cerebrovascular disease. Recent findings indicate that oxidative stress promoting age-related changes of cerebral circulation are involved in neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease. The aim of this study was to evaluate the contribution of cerebral microvessels to the oxidative stress during brain aging, by: (i) assessment of precursors for advanced glycation end products (AGE) formation, (ii) activities of antioxidant enzymes, namely superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione disulfide reductase (GR), and (iii) the activities of metalloproteinases (MMPs), MMP-2 and MMP-9, involved in synaptogenesis and memory consolidation. The experiments were performed on two groups of male Wistar rats: 15 young (3-6 months old) and 15 aged (18-24 months old) animals. The cerebral microvessels were isolated by mechanical homogenization, the concentration of protein carbonyls and the activity of antioxidant enzymes were evaluated by spectrophotometry, and gelatin SDS-PAGE zymography was employed to evaluate MMP-2 and MMP-9 activities. The results showed that, by comparison with young rats, aged brain microvessels contain: (i) approximately 106 % increase of protein carbonyls production; (ii) approximately 68% higher GPx activity, unmodified activities of SOD and GR; (iii) approximately 30% diminishment in MMP-2 activity, and the specific occurrence of MMP-9 enzyme. The data suggest that the age-related changes of microvessels could increase the propensity for cerebral diseases and might represent, at least in part, a prerequisite for the deterioration of mental and physical status in the elderly.

  13. Accumulation of advanced glycation end products, measured as skin autofluorescence, in renal disease.

    Science.gov (United States)

    Hartog, Jasper W L; de Vries, Aiko P J; Lutgers, Helen L; Meerwaldt, Robbert; Huisman, Roel M; van Son, Willem J; de Jong, Paul E; Smit, Andries J

    2005-06-01

    Advanced glycation end products (AGEs) accumulate during renal failure and dialysis. Kidney transplantation is thought to reverse this accumulation by restoring renal function. Using a noninvasive and validated autofluorescence reader, we evaluated AGE levels in 285 transplant recipients (mean age, 52 years; range, 41 to 60 years), 32 dialysis patients (mean age, 56 years; range, 43 to 65 years), and 231 normal control subjects (mean age, 51 years; range, 40 to 65 years). Measurements in transplant recipients were performed for a mean of 73 months (range, 32 to 143 months) after transplantation. Dialysis patients were on dialysis therapy for a mean of 42 months (range, 17 to 107 months). Fluorescence was significantly increased in dialysis patients compared with normal control subjects (2.8 vs. 2.0 arbitrary units [a.u.], P < .0001). Although fluorescence levels were significantly decreased in transplant recipients compared with dialysis patients (2.5 vs. 2.8 a.u., P < .0001), fluorescence in transplant recipients was higher than in controls (2.5 vs. 2.0 a.u., P < .0001). In transplant recipients, fluorescence correlated positively with the duration of dialysis prior to transplantation (R = 0.21, P < .0001), and negatively with creatinine clearance (R = -0.34, P < .0001). No correlation was found between time after transplantation and fluorescence in transplant recipients (R = -0.10, P = .10). Fluorescence in dialysis patients was positively correlated with duration of dialysis (R = 0.36, P = .042). Our results, like those of others, suggest that kidney transplantation does not fully correct increased AGE levels found in dialysis patients. The increased AGE levels in kidney transplant recipients cannot be explained by the differences in renal function alone. The availability of a simple, noninvasive method (AGE-Reader) to measure AGE accumulation may be used to monitor AGE accumulation in a clinical setting as well as in a study setting.

  14. Advanced glycation end products measured by skin autofluorescence in a population with central obesity.

    Science.gov (United States)

    den Engelsen, Corine; van den Donk, Maureen; Gorter, Kees J; Salomé, Philippe L; Rutten, Guy E

    2012-01-01

    Accumulation of advanced glycation end products (AGEs) is enhanced by chronic hyperglycemia and oxidative stress and this process may contribute to the pathogenesis of vascular disease. Skin autofluorescence (AF), a measure of accumulation of AGEs in skin collagen, is associated with vascular disease in patients with diabetes.   Because central obesity enhances oxidative stress people with central obesity might already have increased accumulation of AGEs before diabetes or cardiovascular disease become manifest. To test this hypothesis, we compared the distribution of skin AF and its association with clinical and biochemical parameters in individuals with and without central obesity. Skin AF was measured by a validated AGE Reader in 816 persons with and 431 persons without central obesity, aged 20-70 y. Mean skin AF increased with age and smoking and was higher in centrally obese individuals compared with non-obese individuals (p = 0.001, after adjustment for age and smoking p = 0.13). Mean skin AF in the subgroups without central obesity and without other risk factors (n = 106), central obesity without other risk factors (n = 74) and central obesity with other risk factors (n = 742) was 1.63 ± 0.37, 1.74 ± 0.44 and 1.87 ± 0.43 AU, respectively (p for trend < 0.001, after adjustment for age and smoking p for trend = 0.12). In the group with central obesity age, current smoking, alcohol consumption, waist circumference, creatinine clearance and hs-CRP were independently associated with skin AF (R(2) = 29.4%). Waist circumference hardly contributed to the explained variance. The relationship between waist circumference and skin AF is not as obvious as we hypothesized.

  15. Advanced glycation end product associated skin autofluorescence: a mirror of vascular function?

    Science.gov (United States)

    Hofmann, Britt; Adam, Anne-Catrin; Jacobs, Kathleen; Riemer, Marcus; Erbs, Christian; Bushnaq, Hasan; Simm, Andreas; Silber, Rolf-Edgar; Santos, Alexander Navarrete

    2013-01-01

    Advanced glycation end products (AGEs) seem to be involved in aging as well as in the development of cardiovascular diseases. During aging, AGEs accumulate in extracellular matrix proteins like collagen and contribute to vessel stiffness. Whether non-invasive measurement of AGE accumulation in the skin may reflect vessel function and vessel protein modification is unknown. Herein we set out to analyze the AGE-modifications in the collagens extracted from residual bypass graft material, the skin autofluorescence reflecting the accumulation of AGEs in the body as well as the pulse wave velocity reflecting vessel stiffness. Collagen types I and III (pepsin digestible collagen fraction) were isolated from the veins of 52 patients by proteolysis. The residual collagen fraction was further extracted by collagenase digestion. Collagen was quantified by hydroxyproline assay and AGEs by the AGE intrinsic fluorescence. Skin autofluorescence was measured with an autofluorescence reader; pulse wave velocity with the VICORDER. The collagen AGE autofluorescence in patient vein graft material increased with patient age. The pepsin digestible collagen fraction was significantly less modified in comparison to the collagenase digestible fraction. Decreasing amounts of extracted collagenase digestible collagen correspond with increasing AGE autofluorescence. Skin autofluorescence and vessel stiffness were significantly linked to the AGE autofluorescence of the collagenase digestible collagen fraction from graft material. In conclusion we have found that skin autofluorescence and pulse wave velocity as non-invasive parameters significantly correlate with the AGE contained in graft material and therefore are strong predictors of vessel AGE modifications in patients with coronary heart disease. Whether the analysis of the skin autofluorescence leads to an improvement of the risk stratification in patients suffering from cardiovascular disease has to be further tested.

  16. Advanced glycation end products biphasically modulate bone resorption in osteoclast-like cells.

    Science.gov (United States)

    Li, Ziqing; Li, Chaohong; Zhou, Yuhuan; Chen, Weishen; Luo, Guotian; Zhang, Ziji; Wang, Haixing; Zhang, Yangchun; Xu, Dongliang; Sheng, Puyi

    2016-03-01

    Advanced glycation end products (AGEs) disturb bone remodeling during aging, and this process is accelerated in diabetes. However, their role in modulation of osteoclast-induced bone resorption is controversial, with some studies indicating that AGEs enhance bone resorption and others showing the opposite effect. We determined whether AGEs present at different stages of osteoclast differentiation affect bone resorption differently. Based on increased levels of tartrate-resistant acid phosphatase (TRAP) and cathepsin K (CTSK), we identified day 4 of induction as the dividing time of cell fusion stage and mature stage in RAW264.7 cell-derived osteoclast-like cells (OCLs). AGE-modified BSA (50-400 μg/ml) or control BSA (100 μg/ml) was then added at the beginning of each stage. Results showed that the presence of AGEs at the cell fusion stage reduced pit numbers, resorption area, and CTSK expression. Moreover, expression of receptor activator of nuclear factor-κB (RANK) as well as the number of TRAP-positive cells, nuclei per OCL, actin rings, and podosomes also decreased. However, the presence of AGEs at the mature stage enlarged the resorption area markedly and increased pit numbers slightly. Intriguingly, only the number of nuclei per OCL and podosomes increased. These data indicate that AGEs biphasically modulate bone resorption activity of OCLs in a differentiation stage-dependent manner. AGEs at the cell fusion stage reduce bone resorption dramatically, mainly via suppression of RANK expression in osteoclast precursors, whereas AGEs at the mature stage enhance bone resorption slightly, most likely by increasing the number of podosomes in mature OCLs.

  17. A receptor-based bioadsorbent to target advanced glycation end products in chronic kidney disease

    Science.gov (United States)

    Zhang, Yangrong; Lapidos, Karen A.; Gal-Moscovici, Anca; Sprague, Stuart M.; Ameer, Guillermo A.

    2013-01-01

    The accumulation of advanced glycation end products (AGEs) has been reported to be a major contributor to chronic systemic inflammation. AGEs are not efficiently removed by hemodialysis or the kidney of a chronic kidney disease (CKD) patient. The goal of this study was to develop a receptor for AGEs (RAGE)-based bioadsorbent device that was capable of removing endogenous AGEs from human blood. The extracellular domain of RAGE was immobilized onto agarose beads to generate the bioadsorbent. The efficacy of AGE removal from saline, serum, and whole blood; biological effects of AGE reduction; and hemocompatibility and stability of the bioadsorbent were investigated. The bioadsorbent bound AGE-modified bovine serum albumin (AGE-BSA) with a binding capacity of 0.73 ± 0.07 mg AGE-BSA/ml bioadsorbent. The bioadsorbent significantly reduced the concentration of total AGEs in serum isolated from end stage kidney disease (ESKD) patients by 57%. AGE removal resulted in a significant reduction of vascular cell adhesion molecule-1 (VCAM-1) expression in human endothelial cells and abolishment of osteoclast formation in osteoclast progenitor cells. A hollow fiber device loaded with bioadsorbent reduced endogenous AGEs from recirculated blood to 36% of baseline levels with no significant changes in total protein and albumin concentration. The bioadsorbent maintained AGE-specific binding capacity after freeze-drying and storage for 1 year. This approach provides the foundation for further development of sRAGE-based extracorporeal therapies to selectively deplete serum AGEs from human blood and decrease inflammation in patients with diabetes and/or CKD. PMID:24206165

  18. Advanced glycation end products impair the migration, adhesion and secretion potentials of late endothelial progenitor cells

    Directory of Open Access Journals (Sweden)

    Li Hong

    2012-04-01

    Full Text Available Abstract Background Endothelial progenitor cells (EPCs, especially late EPCs, play a critical role in endothelial maintenance and repair, and postnatal vasculogenesis. Advanced glycation end products (AGEs have been shown to impair EPC functions, such as proliferation, migration and adhesion. However, their role in the regulation of the production of vasoactive substances in late EPCs is less well defined. Methods Passages of 3~5 EPCs, namely late EPCs, were cultured with different concentrations (0~500 μg/ml of AGEs, and the apoptosis, adhesion and migration were subsequently determined. The release of vasoactive substances, such as stromal cell-derived factor-1 (SDF-1, nitric oxide (NO, prostaglandin I2 (PGI2, plasminogen activator inhibitor-1 (PAI-1, tissue plasminogen activator (tPA, and in addition the activity of superoxide dismutase (SOD, were evaluated by ELISA. At the same time, the gene and protein expressions of CXCR4 were assayed by real-time RT-PCR and western-blot. Results AGEs promoted late EPC apoptosis. Moreover, AGEs impaired late EPC migration and adhesion in a concentration-dependent manner. Accordingly, the production of SDF-1 was decreased by AGEs. Although the CXCR4 expressions of late EPCs were up-regulated for AGE concentrations of 50, 100 or 200 μg/ml, a marked decrease was observed for the higher concentration of 500 μg/ml. Furthermore, co-culturing with AGEs decreased the levels of NO, t-PA, PGI2, and the activity of SOD but up-regulated the production of PAI-1. Conclusion Our data provide evidence that AGEs play an important role in impairing late EPC functions, which could contribute to the development of vascular diseases in diabetes.

  19. Dysfunctional protection against advanced glycation due to thiamine metabolism abnormalities in gestational diabetes.

    Science.gov (United States)

    Bartáková, Vendula; Pleskačová, Anna; Kuricová, Katarína; Pácal, Lukáš; Dvořáková, Veronika; Bělobrádková, Jana; Tomandlová, Marie; Tomandl, Josef; Kaňková, Kateřina

    2016-08-01

    While the pathogenic role of dicarbonyl stress and accelerated formation of advanced glycation end products (AGEs) to glucose intolerance and to the development of diabetic complications is well established, little is known about these processes in gestational diabetes mellitus (GDM), a condition pathogenically quite similar to type 2 diabetes. The aims of the present study were (i) to determine plasma thiamine and erythrocyte thiamine diphosphate (TDP) and transketolase (TKT) activity in pregnant women with and without GDM, (ii) to assess relationships between thiamine metabolism parameters and selected clinical, biochemical and anthropometric characteristics and, finally, (iii) to analyse relationship between variability in the genes involved in the regulation of transmembrane thiamine transport (i.e. SLC19A2 and SLC19A3) and relevant parameters of thiamine metabolism. We found significantly lower plasma BMI adjusted thiamine in women with GDM (P = 0.002, Mann-Whitney) while levels of erythrocyte TDP (an active TKT cofactor) in mid-trimester were significantly higher in GDM compared to controls (P = 0.04, Mann-Whitney). However, mid-gestational TKT activity - reflecting pentose phosphate pathway activity - did not differ between the two groups (P > 0.05, Mann-Whitney). Furthermore, we ascertained significant associations of postpartum TKT activity with SNPs SLC19A2 rs6656822 and SLC19A3 rs7567984 (P = 0.03 and P = 0.007, resp., Kruskal-Wallis). Our findings of increased thiamine delivery to the cells without concomitant increase of TKT activity in women with GDM therefore indicate possible pathogenic role of thiamine mishandling in GDM. Further studies are needed to determine its contribution to maternal and/or neonatal morbidity.

  20. Association between Advanced Glycation End Products and Impaired Fasting Glucose: Results from the SALIA Study.

    Directory of Open Access Journals (Sweden)

    Tom Teichert

    Full Text Available Advanced glycation end products (AGEs may contribute to the development of type 2 diabetes and related complications, whereas their role in the early deterioration of glycaemia is unknown. While previous studies used antibody-based methods to quantify AGEs, data from tandem mass spectrometry coupled liquid chromatography (LC-MS/MS-based measurements are limited to patients with known diabetes. Here, we used the LC-MS/MS method to test the hypothesis that plasma AGE levels are higher in individuals with impaired fasting glucose (IFG than in those with normal fasting glucose (NFG. Secondary aims were to assess correlations of plasma AGEs with quantitative markers of glucose metabolism and biomarkers of subclinical inflammation. This study included on 60 women with NFG or IFG (n = 30 each, mean age 74 years from the German SALIA cohort. Plasma levels of free metabolites (3-deoxyfructose, 3-deoxypentosone, 3-deoxypentulose, two hydroimidazolones, oxidised adducts (carboxymethyllysine, carboxyethyllysine, methionine sulfoxide and Nε-fructosyllysine were measured using LC-MS/MS. Plasma concentrations of all tested AGEs did not differ between the NFG and IFG groups (all p>0.05. Associations between plasma levels of AGEs and fasting glucose, insulin and HOMA-IR as a measure of insulin resistance were weak (r between -0.2 and 0.2, all p>0.05. The association between 3-deoxyglucosone-derived hydroimidazolone with several proinflammatory biomarkers disappeared upon adjustment for multiple testing. In conclusion, plasma AGEs assessed by LC-MS/MS were neither increased in IFG nor associated with parameters of glucose metabolism and subclinical inflammation in our study. Thus, these data argue against strong effects of AGEs in the early stages of deterioration of glucose metabolism.

  1. Association between Advanced Glycation End Products and Impaired Fasting Glucose: Results from the SALIA Study

    Science.gov (United States)

    Teichert, Tom; Hellwig, Anne; Peßler, Annette; Hellwig, Michael; Vossoughi, Mohammad; Sugiri, Dorothea; Vierkötter, Andrea; Schulte, Thomas; Freund, Juliane; Roden, Michael; Hoffmann, Barbara; Schikowski, Tamara; Luckhaus, Christian; Krämer, Ursula; Henle, Thomas; Herder, Christian

    2015-01-01

    Advanced glycation end products (AGEs) may contribute to the development of type 2 diabetes and related complications, whereas their role in the early deterioration of glycaemia is unknown. While previous studies used antibody-based methods to quantify AGEs, data from tandem mass spectrometry coupled liquid chromatography (LC-MS/MS)-based measurements are limited to patients with known diabetes. Here, we used the LC-MS/MS method to test the hypothesis that plasma AGE levels are higher in individuals with impaired fasting glucose (IFG) than in those with normal fasting glucose (NFG). Secondary aims were to assess correlations of plasma AGEs with quantitative markers of glucose metabolism and biomarkers of subclinical inflammation. This study included on 60 women with NFG or IFG (n = 30 each, mean age 74 years) from the German SALIA cohort. Plasma levels of free metabolites (3-deoxyfructose, 3-deoxypentosone, 3-deoxypentulose), two hydroimidazolones, oxidised adducts (carboxymethyllysine, carboxyethyllysine, methionine sulfoxide) and Nε-fructosyllysine were measured using LC-MS/MS. Plasma concentrations of all tested AGEs did not differ between the NFG and IFG groups (all p>0.05). Associations between plasma levels of AGEs and fasting glucose, insulin and HOMA-IR as a measure of insulin resistance were weak (r between -0.2 and 0.2, all p>0.05). The association between 3-deoxyglucosone-derived hydroimidazolone with several proinflammatory biomarkers disappeared upon adjustment for multiple testing. In conclusion, plasma AGEs assessed by LC-MS/MS were neither increased in IFG nor associated with parameters of glucose metabolism and subclinical inflammation in our study. Thus, these data argue against strong effects of AGEs in the early stages of deterioration of glucose metabolism. PMID:26018950

  2. Targeting receptor for advanced glycation end products (RAGE) expression induces apoptosis and inhibits prostate tumor growth

    Energy Technology Data Exchange (ETDEWEB)

    Elangovan, Indira; Thirugnanam, Sivasakthivel; Chen, Aoshuang; Zheng, Guoxing [Department of Biomedical Sciences, University of Illinois, College of Medicine, Rockford, IL 61107 (United States); Bosland, Maarten C.; Kajdacsy-Balla, Andre [Department of Pathology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Gnanasekar, Munirathinam, E-mail: mgnanas@uic.edu [Department of Biomedical Sciences, University of Illinois, College of Medicine, Rockford, IL 61107 (United States)

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Targeting RAGE by RNAi induces apoptosis in prostate cancer cells. Black-Right-Pointing-Pointer Silencing RAGE expression abrogates rHMGB1 mediated cell proliferation. Black-Right-Pointing-Pointer Down regulation of RAGE by RNAi inhibits PSA secretion of prostate cancer cells. Black-Right-Pointing-Pointer Knock down of RAGE abrogates prostate tumor growth in vivo. Black-Right-Pointing-Pointer Disruption of RAGE expression in prostate tumor activates death receptors. -- Abstract: Expression of receptor for advanced glycation end products (RAGE) plays a key role in the progression of prostate cancer. However, the therapeutic potential of targeting RAGE expression in prostate cancer is not yet evaluated. Therefore in this study, we have investigated the effects of silencing the expression of RAGE by RNAi approach both in vitro and in vivo. The results of this study showed that down regulation of RAGE expression by RNAi inhibited the cell proliferation of androgen-dependent (LNCaP) and androgen-independent (DU-145) prostate cancer cells. Furthermore, targeting RAGE expression resulted in apoptotic elimination of these prostate cancer cells by activation of caspase-8 and caspase-3 death signaling. Of note, the levels of prostate specific antigen (PSA) were also reduced in LNCaP cells transfected with RAGE RNAi constructs. Importantly, the RAGE RNAi constructs when administered in nude mice bearing prostate tumors, inhibited the tumor growth by targeting the expression of RAGE, and its physiological ligand, HMGB1 and by up regulating death receptors DR4 and DR5 expression. Collectively, the results of this study for the first time show that targeting RAGE by RNAi may be a promising alternative therapeutic strategy for treating prostate cancer.

  3. A receptor-based bioadsorbent to target advanced glycation end products in chronic kidney disease.

    Science.gov (United States)

    Zhang, Yangrong; Lapidos, Karen A; Gal-Moscovici, Anca; Sprague, Stuart M; Ameer, Guillermo A

    2014-06-01

    The accumulation of advanced glycation end products (AGEs) has been reported to be a major contributor to chronic systemic inflammation. AGEs are not efficiently removed by hemodialysis or the kidney of a chronic kidney disease (CKD) patient. The goal of this study was to develop a receptor for AGEs (RAGE)-based bioadsorbent device that was capable of removing endogenous AGEs from human blood. The extracellular domain of RAGE was immobilized onto agarose beads to generate the bioadsorbent. The efficacy of AGE removal from saline, serum, and whole blood; biological effects of AGE reduction; and hemocompatibility and stability of the bioadsorbent were investigated. The bioadsorbent bound AGE-modified bovine serum albumin (AGE-BSA) with a binding capacity of 0.73 ± 0.07 mg AGE-BSA/mL bioadsorbent. The bioadsorbent significantly reduced the concentration of total AGEs in serum isolated from end-stage kidney disease patients by 57%. AGE removal resulted in a significant reduction of vascular cell adhesion molecule-1 expression in human endothelial cells and abolishment of osteoclast formation in osteoclast progenitor cells. A hollow fiber device loaded with bioadsorbent-reduced endogenous AGEs from recirculated blood to 36% of baseline levels with no significant changes in total protein or albumin concentration. The bioadsorbent maintained AGE-specific binding capacity after freeze-drying and storage for 1 year. This approach provides the foundation for further development of soluble RAGE-based extracorporeal therapies to selectively deplete serum AGEs from human blood and decrease inflammation in patients with diabetes and/or CKD.

  4. Molten globule of hemoglobin proceeds into aggregates and advanced glycated end products.

    Directory of Open Access Journals (Sweden)

    Afshin Iram

    Full Text Available Conformational alterations of bovine hemoglobin (Hb upon sequential addition of glyoxal over a range of 0-90% v/v were investigated. At 20% v/v glyoxal, molten globule (MG state of Hb was observed by altered tryptophan fluorescence, high ANS binding, existence of intact heme, native-like secondary structure as depicted by far-UV circular dichroism (CD and ATR-FTIR spectra as well as loss in tertiary structure as confirmed by near-UV CD spectra. In addition, size exclusion chromatography analysis depicted that MG state at 20% v/v glyoxal corresponded to expanded pre-dissociated dimers. Aggregates of Hb were detected at 70% v/v glyoxal. These aggregates of Hb had altered tryptophan environment, low ANS binding, exposed heme, increased β-sheet secondary structure, loss in tertiary structure, enhanced thioflavin T (ThT fluorescence and red shifted Congo Red (CR absorbance. On incubating Hb with 30% v/v glyoxal for 0-20 days, advanced glycation end products (AGEs were detected on day 20. These AGEs were characterised by enhanced tryptophan fluorescence at 450 nm, exposure of heme, increase in intermolecular β-sheets, enhanced ThT fluorescence and red shift in CR absorbance. Comet assay revealed aggregates and AGEs to be genotoxic in nature. Scanning electron microscopy confirmed the amorphous structure of aggregates and branched fibrils of AGEs. The transformation of α-helix to β-sheet usually alters the normal protein to amyloidogenic resulting in a variety of protein conformational disorders such as diabetes, prion and Huntington's.

  5. Bone Formation is Affected by Matrix Advanced Glycation End Products (AGEs) In Vivo.

    Science.gov (United States)

    Yang, Xiao; Mostafa, Ahmed Jenan; Appleford, Mark; Sun, Lian-Wen; Wang, Xiaodu

    2016-10-01

    Advanced glycation end products (AGEs) accumulate in bone extracellular matrix as people age. Although previous evidence shows that the accumulation of AGEs in bone matrix may impose significant effects on bone cells, the effect of matrix AGEs on bone formation in vivo is still poorly understood. To address this issue, this study used a unique rat model with autograft implant to investigate the in vivo response of bone formation to matrix AGEs. Fluorochrome biomarkers were sequentially injected into rats to label the dynamic bone formation in the presence of elevated levels of matrix AGEs. After sacrificing animals, dynamic histomorphometry was performed to determine mineral apposition rate (MAR), mineralized surface per bone surface (MS/BS), and bone formation rate (BFR). Finally, nanoindentation tests were performed to assess mechanical properties of newly formed bone tissues. The results showed that MAR, MS/BS, and BFR were significantly reduced in the vicinity of implant cores with high concentration of matrix AGEs, suggesting that bone formation activities by osteoblasts were suppressed in the presence of elevated matrix AGEs. In addition, MAR and BFR were found to be dependent on the surrounding environment of implant cores (i.e., cortical or trabecular tissues). Moreover, MS/BS and BFR were also dependent on how far the implant cores were away from the growth plate. These observations suggest that the effect of matrix AGEs on bone formation is dependent on the biological milieu around the implants. Finally, nanoindentation test results indicated that the indentation modulus and hardness of newly formed bone tissues were not affected by the presence of elevated matrix AGEs. In summary, high concentration of matrix AGEs may slow down the bone formation process in vivo, while imposing little effects on bone mineralization.

  6. Advanced glycation end products (AGEs) and its receptors in the pathogenesis of hyperthyroidism.

    Science.gov (United States)

    Caspar-Bell, Gudrun; Dhar, Indu; Prasad, Kailash

    2016-03-01

    Oxidative stress has been implicated in the pathogenesis of hyperthyroidism and its complications. Interaction of advanced glycation end products (AGEs) with receptor RAGE (receptor for AGEs) generates reactive oxygen species. Soluble receptor for AGEs (sRAGE) competes with RAGE for binding with AGEs and attenuates the generation of ROS. Low levels sRAGE and high levels AGEs would generate more ROS leading to hyperthyroidism and its complications. The objectives are to determine if levels of serum sRAGE are low and the levels of AGEs and AGEs/sRAGE are high in patients with hyperthyroidism. The study subjects comprised of 33 patients with hyperthyroidism and 20 controls. Levels of serum sRAGE were lower, while that of AGEs and AGEs/sRAGE were higher in patients compared to controls, being significant only for sRAGE and AGEs/sRAGE. When the levels of sRAGE, AGEs, and AGEs/sRAGE were assessed for hyperthyroidism associated with different diseases, the levels of sRAGE were lower in Hashimoto disease, and levels of AGEs were higher in patients with Graves' disease compared to control. The levels of AGEs/sRAGE were elevated in an all except patients with Hashimoto disease. The levels of AGEs, sRAGE, or AGEs/RAGE were not correlated with age, weight, and blood pressures except systolic pressure which was inversely correlated with sRAGE. The levels of sRAGE were negatively correlated with AGEs and AGEs/sRAGE. The levels of AGEs/sRAGE were positively correlated with AGEs. In conclusion, low levels of sRAGE, and high levels of AGEs and AGEs/sRAGE are risk biomarkers in the pathogenesis hyperthyroidism and its complications.

  7. Aspartic acid functions as carbonyl trapper to inhibit the formation of advanced glycation end products by chemical chaperone activity.

    Science.gov (United States)

    Prasanna, Govindarajan; Saraswathi, N T

    2016-05-01

    Advanced glycation end products (AGEs) were implicated in pathology of numerous diseases. In this study, we present the bioactivity of aspartic acid (Asp) to inhibit the AGEs. Hemoglobin and bovine serum albumin (BSA) were glycated with glucose, fructose, and ribose in the presence and absence of Asp (100-200 μM). HbA1c inhibition was investigated using human blood and characterized by micro-column ion exchange chromatography. The effect of methyl glyoxal (MG) on hemoglobin and BSA was evaluated by fluorescence spectroscopy and gel electrophoresis. The effect of MG on red blood cells morphology was characterized by scanning electron micrographs. Molecular docking was performed on BSA with Asp. Asp is capable of inhibiting the formation of fluorescent AGEs by reacting with the reducing sugars. The presence of Asp as supplement in whole blood reduced the HbA1c% from 8.8 to 6.1. The presence of MG showed an increase in fluorescence and the presence of Asp inhibited the glycation thereby the fluorescence was quenched. MG also affected the electrophoretic mobility of hemoglobin and BSA by forming high molecular weight aggregates. Normal RBCs showed typical biconcave shape. MG modified RBCs showed twisted and elongated shape whereas the presence of ASP tends to protect RBC from twisting. Asp interacted with arginine residues of bovine serum albumin particularly ARG 194, ARG 198, and ARG 217 thereby stabilized the protein complex. We conclude that Asp has dual functions as a chemical chaperone to stabilize protein and as a dicarbonyl trapper, and thereby it can prevent the complications caused by glycation.

  8. Life-long endurance running is associated with reduced glycation and mechanical stress in connective tissue

    DEFF Research Database (Denmark)

    Couppé, Christian; Svensson, René B; Grosset, Jean-Francois

    2014-01-01

    Life-long regular endurance exercise is known to counteract the deterioration of cardiovascular and metabolic function and overall mortality. Yet it remains unknown if life-long regular endurance exercise can influence the connective tissue accumulation of advanced glycation endproducts (AGEs...... counteract the aging process in connective tissue by reducing age-related accumulation of AGEs. This may not only benefit skin and tendon but also other long-lived protein tissues in the body. Furthermore, it appears that endurance running yields tendon tissue hypertrophy that may serve to lower the stress...

  9. Non-enzymatic glycation of melamine with sugars and sugar like compounds.

    Science.gov (United States)

    Liu, Weixi; Cohenford, Menashi A; Frost, Leslie; Seneviratne, Champika; Dain, Joel A

    2013-02-01

    Melamine (1,3,5-triazine-2,4,6-triamine) is employed in the manufacture of plastics, laminates and glues, yet, it has been found sometimes added illegally to dairy products to artificially inflate foods' protein content. In 2008, dairy products adulterated with melamine were blamed for the death of several infants in China, a situation that forced Beijing to introduce stricter food safety measures. The objectives of this study were threefold: (1) to investigate the susceptibility of the amine groups of melamine to glycation with D-galactose, D-glucose and lactose, sugars commonly found in milk, (2) to study the rate and extent of melamine's glycation with methylglyoxal, glyoxal and DL-glyceraldehyde, three highly reactive metabolites of D-galactose, D-glucose and lactose, and (3) to characterize, using mass spectrometry, the Advanced Glycation Endproducts (AGEs) of melamine with sugars found commonly in milk and their metabolites. Incubation of D-galactose, D-glucose and lactose with melamine revealed that D-galactose was the most potent glycator of melamine, followed by D-glucose, then lactose. Methylglyoxal, glyoxal, and DL-glyceraldehyde glycated melamine more extensively than D-galactose, with each yielding a broader range of AGEs. The non-enzymatic modification of melamine by sugars and sugar-like compounds warrants further investigation, as this process may influence melamine's toxicity in vivo.

  10. 糖基化终末产物及其受体在糖尿病大鼠胃组织中的分布 (Distribution of advanced glycation end products and their receptor in the stomach of diabetic rats)

    DEFF Research Database (Denmark)

    Tian, Jia Xing; Zhao, Jingbo; Li, Min;

    2015-01-01

    AIM: To observe the distribution of advanced glycation end products (AGEs) and their receptor (RAGE) in the stomach of diabetic rats. METHODS: Diabetes mellitus (DM) and control (CON) rats were reared for eight weeks. Fasting plasma glucose (FPG), glycated serum protein (GSP) and gastric layer......: The expression of AGEs and RAGE is up-regulated in the stomach of diabetic rats. The increased levels of AGE and RAGE in gastric tissue may contribute to diabetic gastrointestinal dysfunction. © 2015 Baishideng Publishing Group Inc. All rights reserved. Key Words: Diabetes mellitus; Stomach; Advanced glycation...... end products; Receptor for advanced glycation end products...

  11. Effect of green tea extract on advanced glycation and cross-linking of tail tendon collagen in streptozotocin induced diabetic rats.

    Science.gov (United States)

    Babu, Pon Velayutham Anandh; Sabitha, Kuruvimalai Ekambaram; Shyamaladevi, Chennam Srinivasulu

    2008-01-01

    Diabetes leads to modification of collagen such as advanced glycation and cross-linking which play an important role in the pathogenesis of diabetes mellitus. We have investigated the effect of green tea on modification of collagen in streptozotocin (60 mg/kg body weight) induced diabetic rats. To investigate the therapeutic effect of green tea, treatment was begun six weeks after the onset of diabetes and green tea extract (300 mg/kg body weight) was given orally for 4 weeks. The collagen content, extent of advanced glycation, advanced glycation end products (AGE) and cross-linking of tail tendon collagen were investigated. Green tea reduced the tail tendon collagen content which increased in diabetic rats. Accelerated advanced glycation and AGE in diabetic animals, as detected by Ehrlich's-positive material and collagen linked fluorescence respectively were reduced significantly by green tea. The solubility of tail tendon collagen decreased significantly in diabetic rats indicating a remarkable increase in the cross-linking, whereas green tea increases the solubility of collagen in diabetic rats. The present study reveals that green tea is effective in reducing the modification of tail tendon collagen in diabetic rats. Thus green tea may have a therapeutic effect in the treatment of glycation induced complications of diabetes.

  12. Bone Aging by Advanced Glycation End Products: A Multiscale Mechanical Analysis.

    Science.gov (United States)

    Ganeko, K; Masaki, C; Shibata, Y; Mukaibo, T; Kondo, Y; Nakamoto, T; Miyazaki, T; Hosokawa, R

    2015-12-01

    The quality and quantity of mandibular bone are essential prerequisites for osseointegrated implants. Only the Hounsfield unit on preoperative computed tomography is currently used as a clinical index. Nevertheless, a considerable mismatch occurs between bone quality and the Hounsfield unit. Loss of bone toughness during aging has been accepted based on empirical evidence, but this concept is unlikely evidence based at the level of mechanical properties. Nonenzymatic bone matrix cross-links associated with advanced glycation end products predominate as a consequence of aging. Thus, loss of tissue integrity could diminish the bone toughening mechanism. Here, we demonstrate an impaired bone toughening mechanism caused by mimicking aging in rabbits on a methionine-rich diet, which enabled an enhanced nonenzymatically cross-linked bone matrix. A 3-point bending test revealed a greater reduction in femoral fracture resistance in rabbits on a methionine-rich diet, despite higher maximum and normalized breaking forces (287.3 N and 88.1%, respectively), than in rabbits on a normal diet (262.2 N and 79.7%, respectively). In situ nanoindentation on mandibular cortical bone obtained from rabbits on a methionine-rich diet did not enable strain rate-dependent stiffening and consequent large-dimensional recovery during rapid loading following constant displacement after a rapid-load indentation test as compared with those in rabbits on a normal diet. Such nanoscale structure-function relationships dictate resistance to cracking propagation at the material level and allow for the overall bone toughening mechanism to operate under large external stressors. The strain-dependent stiffening was likely associated with strain-energy transfer to the superior cross-linked bone matrix network of the normal diet, while the reduction in the enzymatically cross-linked matrix in bone samples from rabbits on a methionine-rich diet likely diminished the intrinsic bone toughening mechanism. The

  13. C-reactive protein, advanced glycation end products and their receptor in type 2 diabetic, elderly patients with mild cognitive impairment

    OpenAIRE

    2015-01-01

    Objective: The aim of the study was to evaluate serum levels of AGEs (advanced glycation end products), RAGE (receptor for advanced glycation end products) and CRP (C-reactive protein) in elderly patients with T2DM with and without mild cognitive impairment (MCI) and to determine the predictors (including AGEs, RAGE and CRP levels) of having MCI in elderly patients with type 2 diabetes.Methods: 276 diabetics elders were screened for MCI (using the Montreal Cognitive Assessment: MoCA score). D...

  14. Plasma advanced glycation end products (AGEs) and NF-κB activity are independent determinants of diastolic and pulse pressure

    DEFF Research Database (Denmark)

    Sourris, Karly C; Lyons, Jasmine G; Dougherty, Sonia L;

    2013-01-01

    Abstract Background: High levels of circulating advanced glycation end products (AGEs) can initiate chronic low-grade activation of the immune system (CLAIS) with each of these factors independently associated with cardiovascular (CV) morbidity and mortality. Therefore, our objective was to chara......Abstract Background: High levels of circulating advanced glycation end products (AGEs) can initiate chronic low-grade activation of the immune system (CLAIS) with each of these factors independently associated with cardiovascular (CV) morbidity and mortality. Therefore, our objective...... was to characterize the relationship between serum AGEs, CLAIS and other risk factors for CV disease in normotensive non-diabetic individuals. Methods: We measured body mass index (BMI), waist-to-hip ratio (WHR), blood pressure, lipid and glucose profile in 44 non-diabetic volunteers (17 female, 27 males......). Carboxymethyl-lysine (CML) was measured by ELISA as a marker for circulating AGEs and NF-κB p65 activity as an inflammatory marker by DNA-binding in peripheral blood mononuclear cells lysates (PBMC). Results: Plasma CML concentrations were related to diastolic blood pressure (r=-0.51, p...

  15. Glycation sites of human plasma proteins are affected to different extents by hyperglycemic conditions in type 2 diabetes mellitus.

    Science.gov (United States)

    Frolov, Andrej; Blüher, Matthias; Hoffmann, Ralf

    2014-09-01

    Glucose can modify proteins in human blood, forming early glycation products (e.g., Amadori compounds), which can slowly degrade to advanced glycation endproducts (AGEs). AGEs contribute significantly to complications of diabetes mellitus and, thus, represent markers of advanced disease stages. They are, however, currently unsuitable for early diagnosis and therapeutic monitoring. Here, we report sensitive strategies to identify and relatively quantify protein glycation sites in human plasma samples obtained from type 2 diabetes mellitus (T2DM) patients and age-matched nondiabetic individuals using a bottom-up approach. Specifically, Amadori peptides were enriched from tryptic digests by boronic acid affinity chromatography, separated by reversed-phase chromatography, and analyzed on-line by high-resolution mass spectrometry. Among the 52 Amadori peptides studied here were 20 peptides resembling 19 glycation sites in six human proteins detected at statistically significantly higher levels in T2DM than in the normoglycemic controls. Four positions appeared to be unique for T2DM within the detection limit. All 19 glycation sites represent promising new biomarker candidates for early diagnosis of T2DM and adequate therapeutic control, as they may indicate early metabolic changes preceding T2DM.

  16. Prevention of non-enzymic glycation of proteins by dietary agents: prospects for alleviating diabetic complications.

    Science.gov (United States)

    Saraswat, Megha; Reddy, P Yadagiri; Muthenna, P; Reddy, G Bhanuprakash

    2009-06-01

    The accumulation of advanced glycation endproducts (AGE) due to non-enzymic glycation of proteins has been implicated in several pathophysiologies associated with ageing and diabetes. The formation of AGE is accelerated in hyperglycaemic conditions, which alter the structure and function of long-lived proteins. Thus inhibition of the formation of AGE is believed to play a role in the prevention of diabetic complications. In the present study we evaluated the antiglycating effect of aqueous extracts of various plant-based foods. The effect of aqueous extracts of these agents in terms of their ability to prevent the accumulation of AGE due to fructose-mediated in vitro glycation of eye lens soluble proteins was investigated. The degree of protein glycation in the absence and presence of dietary extracts was assessed by different complementary methods, i.e. non-tryptophan AGE fluorescence, AGE-induced cross-linking by SDS-PAGE and glyco-oxidative damage by carbonyl assay. Five out of the seventeen agents tested showed significant inhibitory potential against in vitro protein glycation in a dose-dependent manner. Prominent among them were ginger, cumin, cinnamon, black pepper and green tea, which inhibited in vitro AGE formation to lens proteins 40-90 % at 1.0 mg/ml concentration. Assessing their potential to reduce the amount of glycated protein using boronate affinity chromatography and also their ability to prevent the formation of specific antigenic-AGE structures by immunodetection further substantiated the importance of ginger, cumin and cinnamon in reducing AGE burden. These findings indicate the potential of some dietary components to prevent and/or inhibit protein glycation. Thus these dietary agents may be able to be exploited for controlling AGE-mediated diabetic pathological conditions in vivo.

  17. Antihyperglycemic activity and inhibition of advanced glycation end product formation by Cuminum cyminum in streptozotocin induced diabetic rats.

    Science.gov (United States)

    Jagtap, A G; Patil, P B

    2010-01-01

    Cuminum cyminum is widely used as a spice in many countries. The aim of the present study was to investigate the effect of methanolic extract of seeds of C. cyminum (CC) on diabetes, oxidative stress and formation of advanced glycated end products (AGE) and obtain comparison with glibenclamide. In vitro studies indicated that CC inhibited free radicals and AGE formation. Treatment of streptozotocin-diabetic rats with CC and glibenclamide for 28 days caused a reduction in blood glucose, glycosylated hemoglobin, creatinine, blood urea nitrogen and improved serum insulin and glycogen (liver and skeletal muscle) content when compared to diabetic control rats. Significant reduction in renal oxidative stress and AGE was observed with CC when compared to diabetic control and glibenclamide. CC and glibenclamide improved antioxidant status in kidney and pancreas of diabetic rats. Diabetic rats showed increase in rat tail tendon collagen, glycated collagen, collagen linked fluorescence and reduction in pepsin digestion. Treatment with CC significantly improved these parameters when compared to diabetic control and glibenclamide group. Though the antidiabetic effect of CC was comparable to glibenclamide it had better effect in controlling oxidative stress and inhibiting the AGE formation, which are implicated in the pathogenesis of diabetic microvascular complications.

  18. Beneficial effects of metformin and irbesartan on advanced glycation end products (AGEs)-RAGE-induced proximal tubular cell injury.

    Science.gov (United States)

    Ishibashi, Yuji; Matsui, Takanori; Takeuchi, Masayoshi; Yamagishi, Sho-ichi

    2012-03-01

    Advanced glycation end products (AGEs) and their receptor (RAGE) axis contributes to diabetic nephropathy. An oral hypoglycemic agent, metformin may have a potential effect on the inhibition of glycation reactions. Further, since a pathophysiological crosstalk between renin-angiotensin system (RAS) and AGEs-RAGE axis is involved in diabetic nephropathy, it is conceivable that metformin and irbesartan additively could protect against the AGEs-RAGE-induced tubular cell injury. In this study, we addressed the issues. Metformin dose-dependently inhibited the formation of AGEs modification of bovine serum albumin (BSA). Compared with AGEs-modified BSA prepared without metformin (AGEs-MF0), those prepared in the presence of 30 mM or 100 mM metformin (AGEs-MF30 or AGEs-MF100) significantly reduced RAGE mRNA level, reactive oxygen species (ROS) generation, apoptosis, monocyte chemoattractant protein-1 and transforming growth factor-β mRNA level in tubular cells. Irbesartan further inhibited the harmful effects of AGEs-MF0 or AGEs-MF30 on tubular cells. Our present study suggests that combination therapy with metformin and irbesartan may have therapeutic potential in diabetic nephropathy; it could play a protective role against tubular injury in diabetes not only by inhibiting AGEs formation, but also by attenuating the deleterious effects of AGEs via down-regulating RAGE expression and subsequently suppressing ROS generation.

  19. Role of advanced glycation end products (AGEs) and receptor for AGEs (RAGE) in vascular damage in diabetes.

    Science.gov (United States)

    Yamagishi, Sho-ichi

    2011-04-01

    A non-enzymatic reaction between ketones or aldehydes and the amino groups of proteins, lipids and nucleic acids contributes to the aging of macromolecules and to the development and progression of various age-related disorders such as vascular complications of diabetes, Alzheimer's disease, cancer growth and metastasis, insulin resistance and degenerative bone disease. Under hyperglycemic and/or oxidative stress conditions, this process begins with the conversion of reversible Schiff base adducts, and then to more stable, covalently-bound Amadori rearrangement products. Over a course of days to weeks, these early glycation products undergo further reactions and rearrangements to become irreversibly crossed-linked, fluorescent protein derivatives termed advanced glycation end products (AGEs). There is a growing body of evidence that AGE and their receptor RAGE (receptor for AGEs) interaction elicits oxidative stress, inflammatory reactions and thrombosis, thereby being involved in vascular aging and damage. These observations suggest that the AGE-RAGE system is a novel therapeutic target for preventing diabetic vascular complications. In this paper, we review the pathophysiological role of the AGE-RAGE-oxidative stress system and its therapeutic intervention in vascular damage in diabetes. We also discuss here the potential utility of the restriction of food-derived AGEs in diabetic vascular complications.

  20. Analysis of advanced glycation endproducts in dairy products by isotope dilution liquid chromatography-electrospray tandem mass spectrometry. The particular case of carboxymethyllysine.

    Science.gov (United States)

    Delatour, Thierry; Hegele, Jörg; Parisod, Véronique; Richoz, Janique; Maurer, Sarah; Steven, Matthew; Buetler, Timo

    2009-03-20

    A fully validated multiple-transition recording isotope dilution liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantitative determination of N(epsilon)-carboxymethyllysine (CML) and lysine in dairy products is described. Internal standards were [N-1',2'-(13)C(2)]CML and [1,2,3,4,5,6-(13)C(6)-2,6-(15)N(2)]lysine, and the method was validated by evaluating the selectivity, linearity, precision (repeatability and reproducibility) and trueness, using both powder and liquid products. For liquid dairy products, the repeatability and reproducibility was 2.79% and 11.0%, while 4.85% and 4.92% were determined for powder dairy products, respectively. The trueness of the method ranged from -9.6% to -3.6% for powder and from -0.99% to 6.8% for liquid dairy products. The limit of detection for CML was estimated to be 8 ng CML per mg protein while the limit of quantification was 27 ng CML per mg protein. The method encompasses a proteolytic cleavage mediated by enzymatic digestion to reach a complete release of the amino acids prior to a sample cleanup based on solid phase extraction, and followed by LC-MS/MS analysis of CML and lysine residues. To ensure a suitable performance of the enzymatic digestion, CML measurements were compared to values obtained with an acid hydrolysis-mediated proteolysis. Finally, the method was employed for the analysis of CML in various dairy products. The values compare well to the data available in the literature when similar methods were used, even if some discrepancies were observed upon comparison with the results obtained by other techniques such as enzyme-linked immunosorbent assay and GC-MS.

  1. Higher plasma levels of advanced glycation end products are associated with incident cardiovascular disease and all-cause mortality in type 1 diabetes

    DEFF Research Database (Denmark)

    Nin, Johanna W; Jorsal, Anders; Ferreira, Isabel;

    2011-01-01

    OBJECTIVE: To investigate the associations of plasma levels of advanced glycation end products (AGEs) with incident cardiovascular disease (CVD) and all-cause mortality in type 1 diabetes and the extent to which any such associations could be explained by endothelial and renal dysfunction, low...

  2. Skin autofluorescence as a measure of tissue advanced glycation end products deposition is elevated in diabetic patients with peripheral artery disease

    NARCIS (Netherlands)

    De Vos, L.C.; Mulder, D.J.; Dullaart, R.P.F.; Lutgers, H.L.; Smit, A.J.; Kamphuisen, P.W.; Westra, Johanna; Zeebregts, C.J.; Lefrandt, J.D.

    2013-01-01

    Backgrounds and aims: Diabetes mellitus (DM) is an important risk factor for peripheral artery disease (PAD) and associated with a particularly poor prognosis in these patients. Increased glycemic and oxidative stress in DM enhance the accumulation of advanced glycation end products (AGEs), which pl

  3. Age-related accumulation of advanced glycation end-products-albumin, S100β, and the expressions of advanced glycation end product receptor differ in visceral and subcutaneous fat.

    Science.gov (United States)

    Son, Kuk Hui; Son, Myeongjoo; Ahn, Hyosang; Oh, Seyeon; Yum, Yoonji; Choi, Chang Hu; Park, Kook Yang; Byun, Kyunghee

    2016-08-19

    Visceral fat induces more inflammation by activating macrophages than subcutaneous fat, and inflammation is an underlying feature of the pathogeneses of various diseases, including cardiovascular disease and diabetes. Advanced glycation end products (AGEs), S100β, and their receptors, the receptor for advanced glycation end products (RAGE), lead to macrophage activation. However, little information is available regarding the differential accumulations of AGE-albumin (serum albumin modified by AGEs), S100β, or expressions of RAGE in different adipocyte types in fat tissues. In this study, the authors investigated whether age-related AGE-albumin accumulations S100β level, and RAGE expressions differ in subcutaneous and visceral fat tissues. Subcutaneous and visceral fat were harvested from 3- and 28-week-old rats. Macrophage activation was confirmed by Iba1 staining, and AGE-albumin accumulations and RAGE expressions were assessed by confocal microscopy. S100β were analyzed by immunoblotting. It was found that activated macrophage infiltration, AGE-albumin accumulation, and S100β in visceral fat was significantly greater in 28-week-old rats than in 3-week-old rats, but similar in subcutaneous fat. The expression of RAGE in visceral fat was much greater in 28-week-old rats, but its expression in subcutaneous fat was similar in 3- and 28-week-old rats. Furthermore, inflammatory signal pathways (NFκB, TNF-α) and proliferation pathways (FAK) in visceral fat were more activated in 28-week-old rats. These results imply that age-related AGE-albumin accumulation, S100β, and RAGE expression are more prominent in visceral than in subcutaneous fat, suggesting that visceral fat is involved in the pathogenesis of inflammation-induced diseases in the elderly.

  4. Kinetics of advanced glycation end products formation on bovine serum albumin with various reducing sugars and dicarbonyl compounds in equimolar ratios.

    Science.gov (United States)

    Luers, Lars; Rysiewski, Karolina; Dumpitak, Christian; Birkmann, Eva

    2012-04-01

    Reducing sugars and reactive dicarbonyl compounds play a major role in glycation of proteins in vivo. Glycation of proteins is the first step in of a nonenzymatic reaction, resulting in advanced glycation end products (AGEs). AGEs can inactivate proteins or modify their biological activities. Therefore, it is important to understand the mechanism of AGE formation. Here, we systematically analyzed the kinetics of AGE formation in vitro by fluorescence and absorption measurements utilizing a microplate reader system and bovine serum albumin (BSA) as a model protein. Comparing different concentrations of BSA, we applied various reducing sugars and reactive dicarbonyl compounds as AGE-inducing agents at different concentrations. In summary, this experimental setup enabled us to measure the kinetics of AGE formation in an efficient and defined way.

  5. Crosslinking by advanced glycation end products increases the stiffness of the collagen network in human articular cartilage: A possible mechanism through which age is a risk factor for osteoarthritis

    NARCIS (Netherlands)

    Verzijl, N.; Groot, J. de; Zaken, C.B.; Braun-Benjamin, O.; Maroudas, A.; Bank, R.A.; Mizrahi, J.; Schalkwijk, C.G.; Thorpe, S.R.; Baynes, J.W.; Bijlsma, J.W.J.; Lafeber, F.P.J.G.; TeKoppele, J.M.

    2002-01-01

    Objective. Age is an important risk factor for osteoarthritis (OA). During aging, nonenzymatic glycation results in the accumulation of advanced glycation end products (AGEs) in cartilage collagen. We studied the effect of AGE crosslinking on the stiffness of the collagen network in human articular

  6. Cell signaling and receptors in toxicity of advanced glycation end products (AGEs): α-dicarbonyls, radicals, oxidative stress and antioxidants.

    Science.gov (United States)

    Kovacic, Peter; Somanathan, Ratnasamy

    2011-10-01

    Considerable attention has been paid to the toxicity of advanced glycation end products (AGEs), including relation to various illnesses. AGEs, generated nonenzymatically from carbohydrates and proteins, comprises large numbers of simple and more complicated compounds. Many reports deal with a role for receptors (RAGE) and cell signaling, including illnesses and aging. Reactive oxygen species appear to participate in signaling. RAGE include angiotensin II type 1 receptors. Many signaling pathways are involved, such as kinases, p38, p21, TGF-β, NF-κβ, TNF-α, JNK and STAT. A recent review puts focus on α-dicarbonyl metabolites, formed by carbohydrate oxidation, and imine derivatives from protein condensation, as a source via electron transfer (ET) of ROS and oxidative stress (OS). The toxic species have been related to illnesses and aging. Antioxidants alleviate the adverse effects.

  7. Advanced glycation end products, carotid atherosclerosis, and circulating endothelial progenitor cells in patients with end-stage renal disease.

    Science.gov (United States)

    Ueno, Hiroki; Koyama, Hidenori; Fukumoto, Shinya; Tanaka, Shinji; Shoji, Takuhito; Shoji, Tetsuo; Emoto, Masanori; Tahara, Hideki; Inaba, Masaaki; Kakiya, Ryusuke; Tabata, Tsutomu; Miyata, Toshio; Nishizawa, Yoshiki

    2011-04-01

    Numbers of endothelial progenitor cells (EPCs) have been shown to be decreased in subjects with end-stage renal disease (ESRD), the mechanism of which remained poorly understood. In this study, mutual association among circulating EPC levels, carotid atherosclerosis, serum pentosidine, and skin autofluorescence, a recently established noninvasive measure of advanced glycation end products accumulation, was examined in 212 ESRD subjects undergoing hemodialysis. Numbers of circulating EPCs were measured as CD34+ CD133+ CD45(low) VEGFR2+ cells and progenitor cells as CD34+ CD133+ CD45(low) fraction by flow cytometry. Skin autofluorescence was assessed by the autofluorescence reader; and serum pentosidine, by enzyme-linked immunosorbent assay. Carotid atherosclerosis was determined as intimal-medial thickness (IMT) measured by ultrasound. Circulating EPCs were significantly and inversely correlated with skin autofluorescence in ESRD subjects (R = -0.216, P = .002), but not with serum pentosidine (R = -0.079, P = .25). Circulating EPCs tended to be inversely associated with IMT (R = -0.125, P = .069). Intimal-medial thickness was also tended to be correlated positively with skin autofluorescence (R = 0.133, P = .054) and significantly with serum pentosidine (R = 0.159, P = .019). Stepwise multiple regression analyses reveal that skin autofluorescence, but not serum pentosidine and IMT, was independently associated with low circulating EPCs. Of note, skin autofluorescence was also inversely and independently associated with circulating progenitor cells. Thus, tissue accumulated, but not circulating, advanced glycation end products may be a determinant of a decrease in circulating EPCs in ESRD subjects.

  8. Higher plasma soluble Receptor for Advanced Glycation End Products (sRAGE) levels are associated with incident cardiovascular disease and all-cause mortality in type 1 diabetes: a 12-year follow-up study

    DEFF Research Database (Denmark)

    Nin, Johanna W M; Jorsal, Anders; Merces Ferreira, Isabel Maria;

    2010-01-01

    To investigate the associations of plasma levels of soluble receptor for advanced glycation end products (sRAGE) with incident cardiovascular disease (CVD) and all-cause mortality in type 1 diabetes and the extent to which any such associations could be explained by endothelial and renal dysfunct......To investigate the associations of plasma levels of soluble receptor for advanced glycation end products (sRAGE) with incident cardiovascular disease (CVD) and all-cause mortality in type 1 diabetes and the extent to which any such associations could be explained by endothelial and renal...... dysfunction, low-grade inflammation, arterial stiffness, and advanced glycation end products (AGEs)....

  9. Basic and Clinical Research Against Advanced Glycation End Products (AGEs): New Compounds to Tackle Cardiovascular Disease and Diabetic Complications.

    Science.gov (United States)

    Nenna, Antonio; Spadaccio, Cristiano; Lusini, Mario; Ulianich, Luca; Chello, Massimo; Nappi, Francesco

    2015-01-01

    Diabetes is a major risk factor for cardiovascular disease, and recent advances in research indicate that a detailed understanding of the pathophysiology of its effects is mandatory to reduce diabetes-related mortality and morbidity. Advanced Glycation End Products (AGEs) play a central role in the genesis and progression of complications of both type 1 and type 2 diabetes mellitus, and have been found to be important even in non-diabetic patients as a marker of cardiovascular disease. AGEs have a profound impact on patient's prognosis regardless of the glycemic control, and therefore pharmacologic approaches against AGEs accumulation have been proposed over the years to treat cardiovascular diseases, parallel to a more detailed understanding of AGEs pathophysiology. Compounds with anti-AGEs effects are currently under investigation in both pre-clinical and clinical scenarios, and many of the drugs previously used to treat specific diseases have been found to have AGE-inhibitory effects. Some products are still in "bench evaluation", whereas others have been already investigated in clinical trials with conflicting evidences. This review aims at summarizing the mechanisms of AGEs formation and accumulation, and the most relevant issues in pre-clinical and clinical experiences in anti-AGEs treatment in cardiovascular research.

  10. Association of Advanced Glycation End Products with coronary Artery Calcification in Japanese Subjects with Type 2 Diabetes as Assessed by Skin Autofluorescence

    OpenAIRE

    Hangai, Mari; Takebe, Noriko; Honma, Hiroyuki; Sasaki, Atsumi; Chida, Ai; Nakano, Rieko; Togashi, Hirobumi; Nakagawa, Riyuki; Oda, Tomoyasu; Matsui, Mizue; Yashiro, Satoshi; Nagasawa, Kan; Kajiwara, Takashi; Takahashi, Kazuma; Takahashi, Yoshihiko

    2016-01-01

    Aim: Advanced glycation end products (AGE) are considered to be among the critical pathogenic factors involved in the progression of diabetic complications. Skin autofluorescence (AF), a noninvasive measurement of AGE accumulation, has been recognized as a useful and convenient marker for diabetic vascular diseases in Caucasians. This study aimed to evaluate the association of tissue AGE, assessed using skin AF, with coronary artery calcification in Japanese subjects with type 2 diabetes. Met...

  11. Opposing Roles of Membrane and Soluble Forms of the Receptor for Advanced Glycation End Products in Primary Respiratory Syncytial Virus Infection

    OpenAIRE

    2012-01-01

    Respiratory syncytial virus (RSV), a common respiratory pathogen in infants and the older population, causes pulmonary inflammation and airway occlusion that leads to impairment of lung function. Here, we have established a role for receptor for advanced glycation end products (RAGE) in RSV infection. RAGE-deficient (ager−/− ) mice were protected from RSV-induced weight loss and inflammation. This protection correlated with an early increase in type I interferons, later decreases in proinflam...

  12. The receptor for advanced glycation end products (RAGE) affects T cell differentiation in OVA induced asthma.

    Science.gov (United States)

    Akirav, Eitan M; Henegariu, Octavian; Preston-Hurlburt, Paula; Schmidt, Ann Marie; Clynes, Raphael; Herold, Kevan C

    2014-01-01

    The receptor for glycation end products (RAGE) has been previously implicated in shaping the adaptive immune response. RAGE is expressed in T cells after activation and constitutively in T cells from patients with diabetes. The effects of RAGE on adaptive immune responses are not clear: Previous reports show that RAGE blockade affects Th1 responses. To clarify the role of RAGE in adaptive immune responses and the mechanisms of its effects, we examined whether RAGE plays a role in T cell activation in a Th2 response involving ovalbumin (OVA)-induced asthma in mice. WT and RAGE deficient wild-type and OT-II mice, expressing a T cell receptor specific for OVA, were immunized intranasally with OVA. Lung cellular infiltration and T cell responses were analyzed by immunostaining, FACS, and multiplex bead analyses for cytokines. RAGE deficient mice showed reduced cellular infiltration in the bronchial alveolar lavage fluid and impaired T cell activation in the mediastinal lymph nodes when compared with WT mice. In addition, RAGE deficiency resulted in reduced OT-II T cell infiltration of the lung and impaired IFNγ and IL-5 production when compared with WT mice and reduced infiltration when transferred into WT hosts. When cultured under conditions favoring the differentiation of T cells subsets, RAGE deficient T cells showed reduced production of IFNγ but increased production of IL-17. Our data show a stimulatory role for RAGE in T activation in OVA-induced asthma. This role is largely mediated by the effects of RAGE on T cell proliferation and differentiation. These findings suggest that RAGE may play a regulatory role in T cell responses following immune activation.

  13. Specific siRNA Targeting Receptor for Advanced Glycation End Products (RAGE Decreases Proliferation in Human Breast Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    Sheng Liu

    2013-04-01

    Full Text Available Receptor for Advanced Glycation End Products (RAGE is an oncogenic trans-membranous receptor overexpressed in various human cancers. However, the role of RAGE in breast cancer development and proliferation is still unclear. In this study, we demonstrated that RAGE expression levels are correlated to the degree of severity of breast cancer. Furthermore, there is a decrease in the proliferation of all sub-types of breast cancer, MCF-7, SK-Br-3 and MDA-MB-231, as a result of the effect of RAGE siRNA. RAGE siRNA arrested cells in the G1 phase and inhibited DNA synthesis (p < 0.05. Moreover, qRT-PCR and Western Blot results demonstrated that RAGE siRNA decreases the expression of transcriptional factor NF-κB p65 as well as the expression of cell proliferation markers PCNA and cyclinD1. RAGE and RAGE ligands can thus be considered as possible targets for breast cancer management and therapy.

  14. The downregulation of thioredoxin accelerated Neuro2a cell apoptosis induced by advanced glycation end product via activating several pathways.

    Science.gov (United States)

    Ren, Xiang; Ma, Haiying; Qiu, Yuanyuan; Liu, Bo; Qi, Hui; Li, Zeyu; Kong, Hui; Kong, Li

    2015-08-01

    Thioredoxin (Trx), a 12 kDa protein, has different functions in different cellular environments, playing important anti-oxidative and anti-apoptotic roles and regulating the expression of transcription factors. Advanced glycation end products (AGEs) are a heterogeneous group of irreversible adducts from glucose-protein condensation reactions and are considered crucial to the development of diabetic nephropathy, retinopathy, neurodegeneration and atherosclerosis. The aim of this study was to use a Trx inhibitor to investigate the effects and mechanism of Trx down-regulation on AGE-induced Neuro2a cell apoptosis. Neuro2a cells were cultured in vitro and treated with different conditions. The apoptosis and proliferation of Neuro2a cells were detected using flow cytometry, DNA-Ladder and CCK8 assays. Rho 123 was used to detect the mitochondrial membrane potential. ROS generation and caspase3 activity were detected using a DCFH-DA probe and micro-plate reader. Western blotting and real-time PCR were used to detect the expression of proteins and genes. We found that the down-regulation of thioredoxin could accelerate AGE-induced apoptosis in Neuro2a cells. A possible underlying mechanism is that the down-regulation of thioredoxin stimulated the up-regulation of ASK1, p-JNK, PTEN, and Txnip, as well as the down-regulation of p-AKT, ultimately increasing ROS levels and caspase3 activity.

  15. Current perspectives on the health risks associated with the consumption of advanced glycation end products: recommendations for dietary management

    Directory of Open Access Journals (Sweden)

    Palimeri S

    2015-09-01

    Full Text Available Sotiria Palimeri,* Eleni Palioura,* Evanthia Diamanti-KandarakisEndocrine Unit, Medical School University of Athens, Athens, Greece*These authors contributed equally to this workAbstract: Advanced glycation end products (AGEs constitute a complex group of compounds produced endogenously during the aging process and under conditions of hyperglycemia and oxidative stress. AGEs also have an emerging exogenous origin. Cigarette smoke and diet are the two main exogenous sources of AGEs (glycotoxins. Modern Western diets are rich in AGEs which have been implicated in the pathogenesis of several metabolic and degenerative disorders. Accumulating evidence underlies the beneficial effect of the dietary restriction of AGEs not only in animal studies but also in patients with diabetic complications and metabolic diseases. This article reviews the evidence linking dietary glycotoxins to several disorders from diabetic complications and renal failure to liver dysfunction, female reproduction, eye and cognitive disorders as well as cancer. Furthermore, strategies for AGE reduction are discussed with a focus on dietary modification.Keywords: AGEs, dietary glycotoxins, dietary restriction, PCOS, MSR-1, RAGE

  16. Pioglitazone suppresses advanced glycation end product-induced expression of plasminogen activator inhibitor-1 in vascular smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    Xiaochen Yuan; Naifeng Liu

    2011-01-01

    Advanced glycation end products (AGEs) play an important role in vascular complications of diabetes, including fibrinolytic abnormalities.Pioglitazone, a peroxisome proliferator-activated receptor gamma (PPARΥ) agonist, has recently been shown to reduce circulating plasminogen activator inhibitor-1 (PAI-1) levels in diabetes mellitus. In the present study, we investigated the effects of pioglitazone on the expression of local PAI-1 in rat vascular smooth muscle cells (VSMCs) induced by AGEs and the underlying mechanism. The result showed that AGEs could enhance the PAI-1 expression by 5.1-fold in mRNA and 2.7-fold in protein level, as evaluated by real-time RT-PCR and Western blotting,respectively. Pioglitazone was found to down-regulate the AGE-stimulated PAI-1 expression in VSMCs. However, these inhibitory effects were partially attenuated by the PPARΥ antagonist, GW9662. Furthermore, we found that AGEs induced a rapid increase in phosphorylation and activation of extracellular signal-regulated protein kinase 1/2 (ERK 1/2). The ERK kinase inhibitor, UO126, partially prevented the induction of PAI-1 by AGEs. Moreover, pioglitazone was also found to inhibit the phosphorylation of ERKi/2. Taken together, it was concluded that pioglitazone could inhibit AGE-induced PAI-1 expression, which was mediated by the ERK1/2 and PPARΥ pathways. Our findings suggestedpioglitazone had a therapeutic potential in improving fibrinolytic activity, and consequently preventing thromboembolic complications of diabetes and cardiovascular disease.

  17. Contribution of the toxic advanced glycation end-productsreceptor axis in nonalcoholic steatohepatitis-related hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Jun-ichi; Takino; Kentaro; Nagamine; Takamitsu; Hori; Akiko; Sakasai-Sakai; Masayoshi; Takeuchi

    2015-01-01

    Hepatocellular carcinoma(HCC) is one of the most common malignancies worldwide. The main etiologies of HCC are hepatitis B virus and hepatitis C virus(HCV), and non-hepatitis B/non-hepatitis C HCC(NBNCHCC) has also been identified as an etiological factor. Although the incidence of HCV-related HCC in Japan has decreased slightly in recent years, that of NBNC-HCC has increased. The onset mechanism of NBNC-HCC, which has various etiologies, remains unclear; however, nonalcoholic steatohepatitis(NASH), a severe form of nonalcoholic fatty liver disease, is known to be an important risk factor for NBNC-HCC. Among the different advanced glycation end-products(AGEs) formed by the Maillard reaction, glyceraldehyde-derived AGEs, the predominant components of toxic AGEs(TAGE), have been associated with NASH and NBNC-HCC, including NASH-related HCC. Furthermore, the expression of the receptor for AGEs(RAGE) has been correlated with the malignant progression of HCC. Therefore, TAGE induce oxidative stress by binding with RAGE may, in turn, lead to adverse effects, such as fibrosis and malignant transformation, in hepatic stellate cells and tumor cells during NASH or NASH-related HCC progression. The aim of this review was to examine the contribution of the TAGE-RAGE axis in NASH-related HCC.

  18. Glucagon-like peptide-1 protects hippocampal neurons against advanced glycation end product-induced tau hyperphosphorylation.

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    Chen, S; An, F-M; Yin, L; Liu, A-R; Yin, D-K; Yao, W-B; Gao, X-D

    2014-01-03

    We have previously demonstrated that glucagon-like peptide-1 (GLP-1) receptor agonist ameliorated neurodegenerative changes in rat models of diabetes-related Alzheimer's disease (AD), and protected neurons from glucose toxicity in vitro. Herein, we investigated the effects of GLP-1 receptor mediates on cell toxicity and tau hyperphosphorylation induced by advanced glycation end products (AGEs), which are associated with glucose toxicity, and the molecular mechanism in PC12 cells and the primary hippocampal neurons. Our study demonstrated that the similar protection effects of GLP-1 existed in PC12 cells treated with glucose-bovine serum albumin (BSA) in hyperglycemic conditions or with glycoaldehyde-BSA alone. Additionally, glucose-BSA alone did not induce significant cytotoxicity in PC12 cells, but resulted in tau hyperphosphorylation in primary hippocampal neurons in 24h. And we found that GLP-1 could reduce cell tau phosphorylation induced by high glucose or glucose-BSA. Furthermore, our data in the present study suggested that GLP-1 regulated tau phosphorylation induced by AGEs through a signaling pathway involving glycogen synthase kinase 3β (GSK-3β), similarly to the GSK-3β inhibitor, lithium chloride. Our findings suggest that GLP-1 can protect neurons from diabetes-associated AGE insults in vitro, and provide new evidence for a potential therapeutic value of GLP-1 receptor agonist in the treatment of AD especially diabetes-related AD.

  19. Phytoestrogen calycosin-7-O-β-D-glucopyranoside ameliorates advanced glycation end products-induced HUVEC damage.

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    Xu, Youhua; Feng, Liang; Wang, Shanshan; Zhu, Quan; Lin, Jing; Lou, Chihan; Xiang, Ping; He, Bao; Zheng, Zhaoguang; Tang, Dan; Zuo, Guoying

    2011-10-01

    Vasculopathy including endothelial cell (EC) apoptosis and inflammation contributes to the high incidence of stroke and myocardial infarction in diabetic patients. The aim of the present study was to investigate the effect of calycosin-7-O-β-D-glucopyranoside (CG), a phytoestrogen, on advanced glycation end products (AGEs)-induced HUVEC damage. We observed that CG can significantly ameliorate AGEs-induced HUVEC oxidative stress and apoptosis. The ratio of SOD/MDA was significantly increased to the normal level by CG pretreatment. CG preincubation dramatically increased anti-apoptotic Bcl-2 while decreased pro-apoptotic Bax and Bad expressions as detected by immunocytochemistry. Moreover, CG ameliorated macrophage migration and adhesion to HUVEC; the monocyte chemotactic protein-1 and interleukin-6 levels in the culture supernatant were dramatically reduced by CG as determined by ELISA; the expressions of inflammatory proteins including ICAM-1, TGF-β1, and RAGE in both protein and mRNA levels were significantly reduced to the normal level by CG pretreatment as determined by immunocytochemistry and real-time RT-PCR. The intracellular investigation suggests that CG can reverse AGEs-activated ERK1/2 and NF-κB phosphorylation, in which estrogen receptors were involved in. Our results strongly indicate that CG can modulate EC dysfunction by ameliorating AGEs-induced cell apoptosis and inflammation.

  20. Levels of Soluble Receptor for Advanced Glycation End Products in Bronchoalveolar Lavage Fluid in Patients with Various Inflammatory Lung Diseases

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    Kamo, Tetsuro; Tasaka, Sadatomo; Tokuda, Yuriko; Suzuki, Shoji; Asakura, Takanori; Yagi, Kazuma; Namkoong, Ho; Ishii, Makoto; Hasegawa, Naoki; Betsuyaku, Tomoko

    2015-01-01

    Receptor for advanced glycation end products (RAGE) is a multiligand receptor of S100/calgranulins, high-mobility group box 1, and others, and it is associated with the pathogenesis of various inflammatory and circulatory diseases. The soluble form of RAGE (sRAGE) is a decoy receptor and competitively inhibits membrane-bound RAGE activation. In this study, we measured sRAGE levels in bronchoalveolar lavage fluid (BALF) of 78 patients, including 41 with interstitial pneumonia, 11 with sarcoidosis, 9 with respiratory infection, 7 with ARDS, 5 with lung cancer, and 5 with vasculitis. Among them, sRAGE was detectable in BALF of 73 patients (94%). In patients with ARDS and vasculitis, the sRAGE levels were significantly higher than in the control subjects and those with interstitial pneumonia. The sRAGE levels were positively correlated with total cell counts in BALF and serum levels of surfactant protein-D, lactate dehydrogenase, and C-reactive protein. There was an inverse correlation between PaO2/FIO2 ratio and sRAGE levels. These results indicate that sRAGE in BALF might be considered as a biomarker of lung inflammatory disorders, especially ARDS and vasculitis. PMID:27147899

  1. Acute Exposure to a Precursor of Advanced Glycation End Products Induces a Dual Effect on the Rat Pancreatic Islet Function

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    Ghada Elmhiri

    2014-01-01

    Full Text Available Aim. Chronic diseases are the leading cause of death worldwide. Advanced glycation end products, known as AGEs, are a major risk factor for diabetes onset and maintenance. Methylglyoxal (MG, a highly reactive metabolite of glucose, is a precursor for the generation of endogenous AGEs. Methods. In this current study we incubated in vitro pancreatic islets from adult rats in absence or presence of MG (10 μmol/l with different concentrations of glucose and different metabolic components (acetylcholine, epinephrine, potassium, forskolin, and leucine. Results. Different effects of MG on insulin secretion were evidenced. In basal glucose stimulation (5.6 mM, MG induced a significant (P<0.05 increase of insulin secretion. By contrast, in higher glucose concentrations (8.3 mM and 16.7 mM, MG significantly inhibited insulin secretion (P<0.05. In the presence of potassium, forskolin, and epinephrine, MG enhanced insulin secretion (P<0.05, while when it was incubated with acetylcholine and leucine, MG resulted in a decrease of insulin secretion (P<0.05. Conclusion. We suggest that MG modulates the secretion activity of beta-cell depending on its level of stimulation by other metabolic factors. These results provide insights on a dual acute effect of MG on the pancreatic cells.

  2. Soluble Form of Receptor for Advanced Glycation End Products Is Associated with Obesity and Metabolic Syndrome in Adolescents

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    Chih-Tsueng He

    2014-01-01

    Full Text Available The aim of this cross-sectional study was to investigate the relationship between soluble form of receptor for advanced glycation end products (sRAGE, obesity, and metabolic syndrome (MetS in adolescents. A total of 522 male and 561 female adolescents were enrolled into the final analyses. Anthropometric parameters, blood pressure, blood biochemistry, fasting insulin, and plasma sRAGE levels were measured. In males, sRAGE was significantly and inversely correlated with waist circumference (WC, body mass index (BMI, systolic blood pressure, triglyceride (TG, low density lipoprotein cholesterol (LDL-C, and homeostasis model assessment-insulin resistance (HOMA-IR. Only WC and BMI were significantly and inversely correlated with sRAGE in females. Using linear regression analysis adjusting for age and gender, significant association was found between sRAGE and WC, BMI, TG, LDL-C, and HOMA-IR in adolescents of either gender (P<0.05. This association was abolished when further adjusting BMI. In addition, sRAGE was significantly and inversely correlated with the increasing number of components of MetS in males (P for trend = 0.006 but not in females (P for trend = 0.422. In conclusion, plasma sRAGE is associated with obesity and MetS among adolescents. BMI may be the most important determinant of sRAGE levels in adolescents.

  3. Modeling the interaction between quinolinate and the receptor for advanced glycation end products (RAGE: relevance for early neuropathological processes.

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    Iris N Serratos

    Full Text Available The receptor for advanced glycation end products (RAGE is a pattern-recognition receptor involved in neurodegenerative and inflammatory disorders. RAGE induces cellular signaling upon binding to a variety of ligands. Evidence suggests that RAGE up-regulation is involved in quinolinate (QUIN-induced toxicity. We investigated the QUIN-induced toxic events associated with early noxious responses, which might be linked to signaling cascades leading to cell death. The extent of early cellular damage caused by this receptor in the rat striatum was characterized by image processing methods. To document the direct interaction between QUIN and RAGE, we determined the binding constant (Kb of RAGE (VC1 domain with QUIN through a fluorescence assay. We modeled possible binding sites of QUIN to the VC1 domain for both rat and human RAGE. QUIN was found to bind at multiple sites to the VC1 dimer, each leading to particular mechanistic scenarios for the signaling evoked by QUIN binding, some of which directly alter RAGE oligomerization. This work contributes to the understanding of the phenomenon of RAGE-QUIN recognition, leading to the modulation of RAGE function.

  4. Food-advanced glycation end products aggravate the diabetic vascular complications via modulating the AGEs/RAGE pathway.

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    Lv, Xing; Lv, Gao-Hong; Dai, Guo-Ying; Sun, Hong-Mei; Xu, Hui-Qin

    2016-11-01

    The aim of this study was to investigate the effects of high-advanced glycation end products (AGEs) diet on diabetic vascular complications. The Streptozocin (STZ)-induced diabetic mice were fed with high-AGEs diet. Diabetic characteristics, indicators of renal and cardiovascular functions, and pathohistology of pancreas, heart and renal were evaluated. AGEs/RAGE/ROS pathway parameters were determined. During the experiments, the diabetic mice exhibited typical characteristics including weight loss, polydipsia, polyphagia, polyuria, high-blood glucose, and low-serum insulin levels. However, high-AGEs diet effectively aggravated these diabetic characteristics. It also increased the 24-h urine protein levels, serum levels of urea nitrogen, creatinine, c-reactive protein (CRP), low density lipoprotein (LDL), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in the diabetic mice. High-AGEs diet deteriorated the histology of pancreas, heart, and kidneys, and caused structural alterations of endothelial cells, mesangial cells and podocytes in renal cortex. Eventually, high-AGEs diet contributed to the high-AGE levels in serum and kidneys, high-levels of reactive oxygen species (ROS) and low-levels of superoxide dismutase (SOD) in serum, heart, and kidneys. It also upregulated RAGE mRNA and protein expression in heart and kidneys. Our results showed that high-AGEs diet deteriorated vascular complications in the diabetic mice. The activation of AGEs/RAGE/ROS pathway may be involved in the pathogenesis of vascular complications in diabetes.

  5. [Glycation of lens proteins in diabetes and its non-invasive assessment - first experience in the Czech Republic].

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    Škrha, Jan; Šoupal, Jan; Prázný, Martin; Škrha, Jan

    2015-04-01

    Advanced glycation end-products (AGEs) play a crucial role in the pathogenesis of diabetes and its complications. Their accumulation in the lens reflects total glycation rate in the human body. Recently, a new confocal biomicroscope ClearPath DS-120 quickly measuring lens autofluorescence (LAF) has been developed. Our pilot study included 69 patients with diabetes and 49 healthy controls, in all subject LAF was measured and compared with skin autofluorescence (SAF) assessed by AGE-Reader. Both LAF (T1DM: 0,27 ± 0,09; T2DM: 0,22 ± 0,06; controls: 0,17 ± 0,04 AU; p glycated hemoglobin (HbA1c) was rather poor, since HbA1c cannot wholly reflect long-term glycation process. Lens autofluorescence could be a robust marker of long-term diabetes control predicting future complication risks. However, confirmation of such hypothesis will need other and long-term clinical studies.

  6. The effect of valsartan on the expression of the receptor for advanced glycation end products in human glomerular mesangial cells%缬沙坦对人肾小球系膜细胞糖基化终产物受体表达的影响

    Institute of Scientific and Technical Information of China (English)

    钟林娜; 黄国良; 冯敏; 张莹

    2011-01-01

    目的:本实验探讨缬沙坦对糖基化终产物诱导的人肾小球系膜细胞氧化应激水平及糖基化终产物受体(RAGE)表达的影响.方法:体外常规培养人肾小球系膜细胞,运用糖基化修饰的牛血清白蛋白(AGE-BSA)和缬沙坦进行干预,流式细胞术检测细胞内活性氧(ROS),RT-PCR法检测NADPH氧化酶的亚基p47phox的mRNA表达,RT-PCR和细胞免疫化学法检测RAGE的表达量.结果:缬沙坦干预组人肾小球系膜细胞的ROS产生量、NADPH氧化酶的亚基p47phox mRNA表达量、RAGE表达量均低于AGE-BSA组(P<0.05),且缬沙坦的抑制作用呈浓度和时间依赖性.结论:缬沙坦可能通过降低氧化应激水平来抑制RAGE的表达.%Objective: To elucidate the effect of valsartan on human glomerular mesangial cells oxidative stress and the expression of the receptor for advanced glycation end products (RAGE) induced by the advanced glycation end-products (AGEs). Methods: Human glomerular mesangial cells were treated with advanced glycation end-product-bovine serum albumin (AGE-BSA) in the presence of valsartan. The reactive oxygen species( ROS) in cells were measured by Flow cytomeuy, and the mRNA of p47 phox, which was the primary subunits of NADPH oxi-dase, was detected by semi-quantitative reberse transcription polymerase chain reaction (RT-PCR). The mRNA of RAGE was detected by RT-PCR and the RAGE protein was assayed by immunocytochemistry. Results: The product of ROS, and the expression of p47 phox and RAGE in mesangial cells , which were treated with AGE-BSA in the presence of valsartan, were down-regulated compared with the groups treated with AGE-BSA(P < 0.05). Valsartan dose-dependently and ume-dependently inhibited the AGE-elicited overexpression of RAGE, ROS and p47phox in mesangial cells. Conclusion: Valsartan could inhibit RAGE expression through downregularion of oxidative stress.

  7. Advanced oxidation protein products induce chondrocyte apoptosis via receptor for advanced glycation end products-mediated, redox-dependent intrinsic apoptosis pathway.

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    Wu, Qian; Zhong, Zhao-Ming; Zhu, Si-Yuan; Liao, Cong-Rui; Pan, Ying; Zeng, Ji-Huan; Zheng, Shuai; Ding, Ruo-Ting; Lin, Qing-Song; Ye, Qing; Ye, Wen-Bin; Li, Wei; Chen, Jian-Ting

    2016-01-01

    Pro-inflammatory cytokine-induced chondrocyte apoptosis is a primary cause of cartilage destruction in the progression of rheumatoid arthritis (RA). Advanced oxidation protein products (AOPPs), a novel pro-inflammatory mediator, have been confirmed to accumulate in patients with RA. However, the effect of AOPPs accumulation on chondrocyte apoptosis and the associated cellular mechanisms remains unclear. The present study demonstrated that the plasma formation of AOPPs was enhanced in RA rats compared with normal. Then, chondrocyte were treated with AOPPs-modified rat serum albumin (AOPPs-RSA) in vitro. Exposure of chondrocyte to AOPPs activated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and increased expression of NADPH oxidase subunits, which was mediated by receptor for advanced glycation end products (RAGE), but not scavenger receptor CD36. Moreover, AOPPs challenge triggered NADPH oxidase-dependent ROS generation which induced mitochondrial dysfunction and endoplasmic reticulum stress resulted in activation of caspase family that eventually lead to apoptosis. Lastly, blockade of RAGE, instead of CD36, largely attenuated these signals. Our study demonstrated first time that AOPPs induce chondrocyte apoptosis via RAGE-mediated and redox-dependent intrinsic apoptosis pathway in vitro. These data implicates that AOPPs may represent a novel pathogenic factor that contributes to RA progression. Targeting AOPPs-triggered cellular mechanisms might emerge as a promising therapeutic option for patients with RA.

  8. Dietary advanced glycation end products restriction diminishes inflammation markers and oxidative stress in patients with type 2 diabetes mellitus.

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    Luévano-Contreras, Claudia; Garay-Sevilla, Ma Eugenia; Wrobel, Kazimierz; Malacara, Juan M; Wrobel, Katarzyna

    2013-01-01

    The augmented consumption of dietary advanced glycation end products (dAGEs) has been associated with increased oxidative stress and inflammation, however, there is insufficient information over the effect on insulin resistance. The objective of the present study is to investigate the effect of dAGEs restriction on tumor necrosis factor-α (TNF-α), malondialdehyde, C-reactive protein (CRP), and insulin resistance in DM2 patients. We carried out a randomized 6 weeks prospective study in two groups of patients: subjects with a standard diet (n = 13), vs low dAGEs (n = 13). At the beginning and the end of study, we collected anthropometric measurements, and values of circulating glucose, HbA1c, lipids, insulin, serum AGEs, CRP, TNF-α and malondialdehyde. Anthropometric measurements, glucose, and lipids were similar in both groups at base line and at the end of the study. Estimation of basal dAGEs was similar in both groups; after 6 weeks it was unchanged in the standard group but in the low dAGEs group decreased by 44% (p<0.0002). Changes in TNF-α levels were different under standard diet (12.5 ± 14.7) as compared with low dAGEs (-18.36 ± 17.1, p<0.00001); changes in malondialdehyde were different in the respective groups (2.0 ± 2.61 and -0.83 ± 2.0, p<0.005) no changes were found for insulin levels or HOMA-IR. In conclusion, The dAGEs restriction decreased significantly TNF-α and malondialdehyde levels.

  9. Skin autofluorescence, a measure of cumulative metabolic stress and advanced glycation end products, predicts mortality in hemodialysis patients.

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    Meerwaldt, Robbert; Hartog, Jasper W L; Graaff, Reindert; Huisman, Roel J; Links, Thera P; den Hollander, Nynke C; Thorpe, Susan R; Baynes, John W; Navis, Gerjan; Gans, Rijk O B; Smit, Andries J

    2005-12-01

    Tissue advanced glycation end products (AGE) are a measure of cumulative metabolic stress and trigger cytokines driven inflammatory reactions. AGE are thought to contribute to the chronic complications of diabetes and ESRD. Tissue autofluorescence is related to the accumulation of AGE. Therefore, skin autofluorescence (AF) may provide prognostic information on mortality in hemodialysis (HD) patients. Skin AF was measured noninvasively with an AF reader at baseline in 109 HD patients. Overall and cardiovascular mortality was monitored prospectively during a period of 3 yr. The AF reader was validated against AGE contents in skin biopsies from 29 dialysis patients. Forty-two of the 109 (38.5%) HD patients died. Cox regression analysis showed that AF was an independent predictor of overall and cardiovascular mortality (for overall mortality odds ratio [OR] 3.9), as were pre-existing cardiovascular disease (CVD; OR 3.1), C-reactive protein (OR 1.1), and serum albumin (OR 0.3). Multivariate analysis revealed that 65% of the variance in AF could be attributed to the independent effects of age, dialysis and renal failure duration, presence of diabetes, triglycerides levels, and C-reactive protein. AF was also independently linked to the presence of CVD at baseline (OR 8.8; P < 0.001). AF correlated with collagen-linked fluorescence (r = 0.71, P < 0.001), pentosidine (r = 0.75, P < 0.001), and carboxy(m)ethyllysine (both r = 0.45, P < 0.01). Skin AF is a strong and independent predictor of mortality in ESRD. This supports a role for AGE as a contributor to mortality and CVD and warrants interventions specifically aimed at AGE accumulation.

  10. Efek Kortikosteroid Dosis Rendah terhadap Kadar Soluble Receptor for Advanced Glycation End Products Mencit Balb/C Model Sepsis

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    Diding Heri Prasetyo

    2015-03-01

    Full Text Available The use of low-dose corticosteroids in the management of early sepsis is still under debate. Soluble receptor for advanced glycation end products (sRAGE is a biomarker of severity and poor outcome of sepsis. This study aimed to analyze the effects of the use of low-dose corticosteroids on sRAGE serum levels in Balb/C mice model of early sepsis. This study was an experimental research laboratory study with 30 male Balb/C mice which divided into control, sepsis and sepsis+low-dose corticosteroids groups. The study was conducted at Histology and Biomedical Laboratory, Faculty of Medicine, Sebelas Maret University, Surakarta, from June to December 2013. Sepsis was induced in the male Balb/C mice by inoculation with an intraperitoneally (i.p. injection of lipopoly-saccharide/LPS (E. coli with a dose of 0.1 mg/mice/i.p.for sepsis mice model. Control mice were not inoculated during the study. Low-dose corticosteroids used was methyl prednisolone at a dose of 0.05 mg/mice/day/i.p. Levels of sRAGE 54.29±16.28 pg/mL in control group, 78.12±13.38 pg/mL in sepsis group, and 63.39±11.07 pg/mL in low-dose corticosteroids group. Low-dose corticosteroids significantly decreased sRAGE level (p=0.044 compared to the sepsis group. In conclusion, the use of low-dose corticosteroids reduces levels of sRAGE in early sepsis.

  11. Advanced glycation end products promote hepatosteatosis by interfering with SCAP-SREBP pathway in fructose-drinking mice.

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    Mastrocola, Raffaella; Collino, Massimo; Rogazzo, Mara; Medana, Claudio; Nigro, Debora; Boccuzzi, Giuseppe; Aragno, Manuela

    2013-09-15

    Clinical studies have linked the increased consumption of fructose to the development of obesity, dyslipidemia, and impaired glucose tolerance, and a role in hepatosteatosis development is presumed. Fructose can undergo a nonenzymatic reaction from which advanced glycation end products (AGEs) are derived, leading to the formation of dysfunctional, fructosylated proteins; however, the in vivo formation of AGEs from fructose is still less known than that from glucose. In the present study C57Bl/6J mice received 15% (wt/vol) fructose (FRT) or 15% (wt/vol) glucose (GLC) in water to drink for 30 wk, resembling human habit to consume sugary drinks. At the end of the protocol both FRT- and GLC-drinking mice had increased fasting glycemia, glucose intolerance, altered plasma lipid profile, and marked hepatosteatosis. FRT mice had higher hepatic triglycerides deposition than GLC, paralleled by a greater increased expression and activity of the sterol regulatory element-binding protein 1 (SREBP1), the transcription factor responsible for the de novo lipogenesis, and of its activating protein SCAP. LC-MS analysis showed a different pattern of AGE production in liver tissue between FRT and GLC mice, with larger amount of carboxymethyl lysine (CML) generated by fructose. Double immunofluorescence and coimmunoprecipitation analysis revealed an interaction between CML and SCAP that could lead to prolonged activation of SREBP1. Overall, the high levels of CML and activation of SCAP/SREBP pathway associated to high fructose exposure here reported may suggest a key role of this signaling pathway in mediating fructose-induced lipogenesis.

  12. Increased proinflammatory endothelial response to S100A8/A9 after preactivation through advanced glycation end products

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    Greten Johannes

    2006-03-01

    Full Text Available Summary Background Atherosclerosis is an inflammatory disease in which a perpetuated activation of NFkappaB via the RAGE (receptor for advanced glycation end products-MAPK signalling pathway may play an important pathogenetic role. As recently S100 proteins have been identified as ligands of RAGE, we sought to determine the effects of the proinflammatory heterodimer of S100A8/S100A9 on the RAGE-NFkappaB mediated induction of proinflammatory gene expression. Methods Human umbilical vein endothelial cells (HUVEC were preincubated for 72 h with AGE-albumin or unmodified albumin for control, whereas AGE-albumin induction resulted in an upregulation of RAGE. Following this preactivation, cells were stimulated for 48 h with heterodimeric human recombinant S100A8/S100A9. Results Heterodimeric S100A8/S100A9 enhanced secretion of IL-6, ICAM-1, VCAM-1 and MCP1 in AGE-albumin pretreated HUVEC in a dose dependent manner. These effects could not be detected after stimulation with the homodimeric proteins S100A8, S100A9, S100A1 and S100B. The effects of heterodimeric S100A8/S100A9 were reduced by inhibition of the MAP-kinase pathways ERK1/2 and p38 by PD 98059 and SB 203580, respectively. Conclusion The heterodimeric S100A8/S100A9 might therefore play a hitherto unknown role in triggering atherosclerosis in diabetes and renal failure, pathophysiological entities associated with a high AGE burden. Thus, blocking heterodimeric S100A8/S100A9 might represent a novel therapeutic modality in treating atherosclerosis.

  13. Reduction of advanced-glycation end products levels and inhibition of RAGE signaling decreases rat vascular calcification induced by diabetes.

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    Mathieu R Brodeur

    Full Text Available Advanced-glycation end products (AGEs were recently implicated in vascular calcification, through a process mediated by RAGE (receptor for AGEs. Although a correlation between AGEs levels and vascular calcification was established, there is no evidence that reducing in vivo AGEs deposition or inhibiting AGEs-RAGE signaling pathways can decrease medial calcification. We evaluated the impact of inhibiting AGEs formation by pyridoxamine or elimination of AGEs by alagebrium on diabetic medial calcification. We also evaluated if the inhibition of AGEs-RAGE signaling pathways can prevent calcification. Rats were fed a high fat diet during 2 months before receiving a low dose of streptozotocin. Then, calcification was induced with warfarin. Pyridoxamine was administered at the beginning of warfarin treatment while alagebrium was administered 3 weeks after the beginning of warfarin treatment. Results demonstrate that AGEs inhibitors prevent the time-dependent accumulation of AGEs in femoral arteries of diabetic rats. This effect was accompanied by a reduced diabetes-accelerated calcification. Ex vivo experiments showed that N-methylpyridinium, an agonist of RAGE, induced calcification of diabetic femoral arteries, a process inhibited by antioxidants and different inhibitors of signaling pathways associated to RAGE activation. The physiological importance of oxidative stress was demonstrated by the reduction of femoral artery calcification in diabetic rats treated with apocynin, an inhibitor of reactive oxygen species production. We demonstrated that AGE inhibitors prevent or limit medial calcification. We also showed that diabetes-accelerated calcification is prevented by antioxidants. Thus, inhibiting the association of AGE-RAGE or the downstream signaling reduced medial calcification in diabetes.

  14. The advanced glycation end product-lowering agent ALT-711 is a low-affinity inhibitor of thiamine diphosphokinase.

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    Krautwald, Martina; Leech, Dale; Horne, Stacey; Steele, Megan L; Forbes, Josephine; Rahmadi, Anton; Griffith, Renate; Münch, Gerald

    2011-08-01

    Advanced glycation end products (AGEs) are involved in age-related diseases, including the complications of diabetes and chronic renal impairment with arterial stiffening. Alagebrium chloride (ALT-711) is an AGE-lowering agent with beneficial effects in renal structural and functional parameters in diabetes, decreased diabetes-accelerated atherosclerosis, and age-related myocardial stiffening. ALT-711 exhibits a structural homology to thiamine, and it was suggested to interfere with thiamine metabolism. Thiamine is converted to thiamine diphosphate (TDP) by thiamine diphosphokinase (TDPK). TDP is a cofactor for pyruvate dehydrogenase, α-ketoglutarate dehydrogenase and transketolase. A decreased activity of these enzymes due to TDP deficiency results in disorders such as beriberi and Wernicke-Korsakoff syndrome. Therefore, we investigated whether ALT-711 is an inhibitor of TDPK. Molecular modeling studies showed that ALT-711 fits into the thiamine-binding pocket of TDPK, and there are three interactions between the thiazolium ring and the enzyme, as well as parallel stacking between the phenyl ring and the indole ring of Trp222B. Enzyme kinetic experiments also showed that ALT-711 dose-dependently decreased TDPK activity with K(i)s, calculated by different experiments and fitting models ranging from 0.88 to 1.09 mM. Fitting of the kinetic data favored mixed-mode inhibition with a major role for competitive inhibition. In summary, our results suggest that ALT-711 is a low-affinity inhibitor of TDPK, but is unlikely to interfere with thiamine metabolism at therapeutic concentrations. However, when new AGE-crosslink breakers based on thiamine are designed, care should be taken that they do not act as more potent competitive inhibitors than ALT-711.

  15. Advanced Glycation End Products Inhibit the Proliferation of Human Umbilical Vein Endothelial Cells by Inhibiting Cathepsin D

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    Li, Yuan; Chang, Ye; Ye, Ning; Dai, Dongxue; Chen, Yintao; Zhang, Naijin; Sun, Guozhe; Sun, Yingxian

    2017-01-01

    We aimed to investigate the effect of advanced glycation end products (AGEs) on the proliferation and migration ability of human umbilical vein endothelial cells (HUVECs). Cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay, real-time cell analyzer and 5-Ethynyl-2′-deoxyuridine (EdU) staining. Cell migration was detected by wound-healing and transwell assay. AGEs significantly inhibited the proliferation and migration of HUVECs in a time-and dose-dependent way. Western blotting revealed that AGEs dramatically increased the expression of microtubule-associated protein 1 light chain 3 (LC3) II/I and p62. Immunofluorescence of p62 and acridine orange staining revealed that AGEs significantly increased the expression of p62 and the accumulation of autophagic vacuoles, respectively. Chloroquine (CQ) could further promote the expression of LC3 II/I and p62, increase the accumulation of autophagic vacuoles and promote cell injury induced by AGEs. In addition, AGEs reduced cathepsin D (CTSD) expression in a time-dependent way. Overexpression of wild-type CTSD significantly decreased the ratio of LC 3 II/I as well as p62 accumulation induced by AGEs, but overexpression of catalytically inactive mutant CTSD had no such effects. Only overexpression of wild-type CTSD could restore the proliferation of HUVECs inhibited by AGEs. However, overexpression of both wild-type CTSD and catalytically inactive mutant CTSD could promote the migration of HUVECs inhibited by AGEs. Collectively, our study found that AGEs inhibited the proliferation and migration in HUVECs and promoted autophagic flux, which in turn played a protective role against AGEs-induced cell injury. CTSD, in need of its catalytic activity, may promote proliferation in AGEs-treated HUVECs independent of the autophagy-lysosome pathway. Meanwhile, CTSD could improve the migration of AGEs-treated HUVECs regardless of its enzymatic activity. PMID:28218663

  16. Central and peripheral blood pressures in relation to plasma advanced glycation end products in a Chinese population.

    Science.gov (United States)

    Huang, Q-F; Sheng, C-S; Kang, Y-Y; Zhang, L; Wang, S; Li, F-K; Cheng, Y-B; Guo, Q-H; Li, Y; Wang, J-G

    2016-07-01

    We investigated the association of plasma AGE (advanced glycation end product) concentration with central and peripheral blood pressures and central-to-brachial blood pressure amplification in a Chinese population. The study subjects were from a newly established residential area in the suburb of Shanghai. Using the SphygmoCor system, we recorded radial arterial waveforms and derived aortic waveforms by a generalized transfer function and central systolic and pulse pressure by calibration for brachial blood pressure measured with an oscillometric device. The central-to-brachial pressure amplification was expressed as the central-to-brachial systolic blood pressure difference and pulse pressure difference and ratio. Plasma AGE concentration was measured by the enzyme-linked immunosorbent assay method and logarithmically transformed for statistical analysis. The 1051 participants (age, 55.1±13.1 years) included 663 women. After adjustment for sex, age and other confounding factors, plasma AGE concentration was associated with central but not peripheral blood pressures and with some of the pressure amplification indexes. Indeed, each 10-fold increase in plasma AGE concentration was associated with 2.94 mm Hg (P=0.04) higher central systolic blood pressure and 2.39% lower central-to-brachial pulse pressure ratio (P=0.03). In further subgroup analyses, the association was more prominent in the presence of hypercholesterolemia (+8.11 mm Hg, P=0.008) for central systolic blood pressure and in the presence of overweight and obesity (-4.89%, P=0.009), diabetes and prediabetes (-6.26%, P=0.10) or current smoking (-6.68%, P=0.045) for central-to-brachial pulse pressure ratio. In conclusion, plasma AGE concentration is independently associated with central systolic blood pressure and pulse pressure amplification, especially in the presence of several modifiable cardiovascular risk factors.

  17. Evaluation of autofluorescent property of hemoglobin-advanced glycation end product as a long-term glycemic index of diabetes.

    Science.gov (United States)

    Gopalkrishnapillai, Bijukumar; Nadanathangam, Vigneshwaran; Karmakar, Nivedita; Anand, Sneh; Misra, Anoop

    2003-04-01

    Current methods for measuring long-term glycemia in patients with diabetes are HbA(1c) and advanced glycation end products (AGEs), which are estimated by phenyl boronate affinity chromatography and competitive enzyme-linked immunosorbent assay, respectively. In this study, we hypothesize that the intrinsic fluorescence property of hemoglobin-AGE (Hb-AGE) may be a simple, accurate, and therefore better index for long-term glycemic status due to its highly specific nature and longer half-life. To establish this contention, in vitro and in vivo experiments were carried out. The former was performed by incubating commercially available hemoglobin with 5 and 20 mmol/l glucose and the latter through experimentally induced (streptozotocin) diabetes in an animal model (male Wistar rats) to identify the new fluorophore formed due to the nonenzymatic glycosylation of hemoglobin. An adduct exhibiting fluorescence at 308/345 nm of excitation/emission wavelengths has been identified and its time-dependent formation established. Under in vitro conditions, the first appearance of the new fluorophore was noticed only after a period of 2 months, whereas under in vivo conditions, it increased significantly after 2 months of hyperglycemia. Consistent with the observations, studies on patients with type 2 diabetes demonstrated an elevated level of this new fluorescent adduct in patients with persisting high levels of plasma glucose for >2 months. Based on the results obtained, Hb-AGE appears to be an efficient fluorescence-based biosensing molecule for the long-term monitoring of glycemic control in diabetes.

  18. Advanced glycation end products (AGEs) increase human mesangial foam cell formation by increasing Golgi SCAP glycosylation in vitro.

    Science.gov (United States)

    Yuan, Yang; Zhao, Lei; Chen, Yaxi; Moorhead, John F; Varghese, Zac; Powis, Stephen H; Minogue, Shane; Sun, Zilin; Ruan, Xiong Z

    2011-07-01

    Advanced glycation end products (AGEs) is one of the causative factors of diabetic nephropathy, which is associated with lipid accumulation in glomeruli. This study was designed to investigate whether N(ε)-(carboxymethyl) lysine (CML; a member of the AGEs family) increases lipid accumulation by impairing the function of sterol-regulatory element binding protein (SREBP) cleavage-activating protein (SCAP) in human mesangial cells (HMCs). Intracellular cholesterol content was assessed by Oil Red O staining and quantitative assay. The expression of molecules controlling cholesterol homeostasis was examined using real-time quantitative RT-PCR and Western blotting. The activity of Golgi-processing enzymes was determined using enzyme-based methods, and the translocation of SCAP from the endoplasmic reticulum (ER) to the Golgi was detected by confocal microscopy. CML increased cholesterol accumulation in HMCs. Exposure to CML increased expression and abnormal translocation of SCAP from the ER to the Golgi even in the presence of a high concentration of LDL. The increased SCAP translocation carried more SREBP-2 to the Golgi for activation by proteolytic cleavages, enhancing transcription of 3-hydroxy-3-methylclutaryl-CoA reductase and the LDL receptor. CML increased Golgi mannosidase activity, which may enhance glycosylation of SCAP. This prolonged the half-life and enhanced recycling of SCAP between the ER and the Golgi. The effects of CML were blocked by inhibitors of Golgi mannosidases. AGEs (CML) increased lipid synthesis and uptake, thereby causing foam cell formation via increasing transcription and protein glycosylation of SCAP in HMCs. These data imply that inhibitors of Golgi-processing enzymes might have a potential renoprotective role in prevention of mesangial foam cell formation.

  19. Advanced Glycation End Products Inhibit the Proliferation of Human Umbilical Vein Endothelial Cells by Inhibiting Cathepsin D

    Directory of Open Access Journals (Sweden)

    Yuan Li

    2017-02-01

    Full Text Available We aimed to investigate the effect of advanced glycation end products (AGEs on the proliferation and migration ability of human umbilical vein endothelial cells (HUVECs. Cell proliferation was detected by methyl thiazolyl tetrazolium (MTT assay, real-time cell analyzer and 5-Ethynyl-2′-deoxyuridine (EdU staining. Cell migration was detected by wound-healing and transwell assay. AGEs significantly inhibited the proliferation and migration of HUVECs in a time-and dose-dependent way. Western blotting revealed that AGEs dramatically increased the expression of microtubule-associated protein 1 light chain 3 (LC3 II/I and p62. Immunofluorescence of p62 and acridine orange staining revealed that AGEs significantly increased the expression of p62 and the accumulation of autophagic vacuoles, respectively. Chloroquine (CQ could further promote the expression of LC3 II/I and p62, increase the accumulation of autophagic vacuoles and promote cell injury induced by AGEs. In addition, AGEs reduced cathepsin D (CTSD expression in a time-dependent way. Overexpression of wild-type CTSD significantly decreased the ratio of LC 3 II/I as well as p62 accumulation induced by AGEs, but overexpression of catalytically inactive mutant CTSD had no such effects. Only overexpression of wild-type CTSD could restore the proliferation of HUVECs inhibited by AGEs. However, overexpression of both wild-type CTSD and catalytically inactive mutant CTSD could promote the migration of HUVECs inhibited by AGEs. Collectively, our study found that AGEs inhibited the proliferation and migration in HUVECs and promoted autophagic flux, which in turn played a protective role against AGEs-induced cell injury. CTSD, in need of its catalytic activity, may promote proliferation in AGEs-treated HUVECs independent of the autophagy-lysosome pathway. Meanwhile, CTSD could improve the migration of AGEs-treated HUVECs regardless of its enzymatic activity.

  20. Advanced Glycation End Product (AGE) Accumulation in the Skin is Associated with Depression

    DEFF Research Database (Denmark)

    van Dooren, Fleur E P; Pouwer, Frans; Schalkwijk, Casper G

    2017-01-01

    the Maastricht Study (N = 862, mean age 59.8 ± 8.5 years, 55% men). AGE accumulation was measured with skin autofluorescence (SAF) by use of the AGE Reader. Plasma levels of protein-bound pentosidine were measured with high-performance liquid chromatography and fluorescence detection. Nε......-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL) were measured with ultraperformance liquid chromatography and tandem mass spectrometry. Depressive symptoms and depressive disorder were assessed by the nine-item Patient Health Questionnaire and the Mini-International Neuropsychiatric Interview. RESULTS: Higher......BACKGROUND: Depression is a highly prevalent disease with a high morbidity and mortality risk. Its pathophysiology is not entirely clear. However, type 2 diabetes is an important risk factor for depression. One mechanism that may explain this association may include the formation of advanced...

  1. Generation of Soluble Advanced Glycation End Products Receptor (sRAGE)-Binding Ligands during Extensive Heat Treatment of Whey Protein/Lactose Mixtures Is Dependent on Glycation and Aggregation.

    Science.gov (United States)

    Liu, Fahui; Teodorowicz, Małgorzata; Wichers, Harry J; van Boekel, Martinus A J S; Hettinga, Kasper A

    2016-08-24

    Heating of protein- and sugar-containing materials is considered the primary factor affecting the formation of advanced glycation end products (AGEs). This study aimed to investigate the influence of heating conditions, digestion, and aggregation on the binding capacity of AGEs to the soluble AGE receptor (sRAGE). Samples consisting of mixtures of whey protein and lactose were heated at 130 °C. An in vitro infant digestion model was used to study the influence of heat treatment on the digestibility of whey proteins. The amount of sRAGE-binding ligands before and after digestion was measured by an ELISA-based sRAGE-binding assay. Water activity did not significantly affect the extent of digestibility of whey proteins dry heated at pH 5 (ranging from 3.3 ± 0.2 to 3.6 ± 0.1% for gastric digestion and from 53.5 ± 1.5 to 64.7 ± 1.1% for duodenal digestion), but there were differences in cleavage patterns of peptides among the samples heated at different pH values. Formation of sRAGE-binding ligands depended on the formation of aggregates and was limited in the samples heated at pH 5. Moreover, the sRAGE-binding activity of digested sample was changed by protease degradation and correlated with the digestibility of samples. In conclusion, generation of sRAGE-binding ligands during extensive heat treatment of whey protein/lactose mixtures is limited in acidic heating condition and dependent on glycation and aggregation.

  2. Advanced glycation end products promote differentiation of CD4(+) T helper cells toward pro-inflammatory response.

    Science.gov (United States)

    Han, Xiao-qun; Gong, Zuo-jiong; Xu, San-qing; Li, Xun; Wang, Li-kun; Wu, Shi-min; Wu, Jian-hong; Yang, Hua-fen

    2014-02-01

    This study investigated the effect of advanced glycation end products (AGEs) on differentiation of naïve CD4(+) T cells and the role of the receptor of AGEs (RAGE) and peroxisome proliferator-activated receptors (PPARs) activity in the process in order to gain insight into the mechanism of immunological disorders in diabetes. AGEs were prepared by the reaction of bovine serum albumin (BSA) with glucose. Human naïve CD4(+) T cells, enriched from blood of healthy adult volunteers with negative selection assay, were cultured in vitro and treated with various agents including AGEs, BSA, high glucose, PGJ2 and PD68235 for indicated time. In short hairpin (sh) RNA knock-down experiment, naïve CD4(+) T cells were transduced with media containing shRNA-lentivirus generated from lentiviral packaging cell line, Lent-X(TM) 293 T cells. Surface and intracellular cytokine stainings were used for examination of CD4(+) T cell phenotypes, and real-time PCR and Western blotting for detection of transcription factor mRNA and protein expression, respectively. The suppressive function of regulatory T (Treg) cells was determined by a [(3)H]-thymidine incorporation assay. The results showed that AGEs induced higher pro-inflammatory Th1/Th17 cells differentiated from naïve CD4(+) T cells than the controls, whereas did not affect anti-inflammatory Treg cells. However, AGEs eliminated suppressive function of Treg cells. In addition, AGEs increased RAGE mRNA expression in naïve CD4(+) T cells, and RAGE knock-down by shRNA eliminated the effect of AGEs on the differentiation of CD4(+) T cells and the reduction of suppressive function of Treg cells. Furthermore, AGEs inhibited the mRNA expression of PPARγ, not PPARα PPARγ agonist, PGJ2, inhibited the effect of AGEs on naïve CD4(+) T cell differentiation and reversed the AGE-reduced suppressive function of Treg cells; on the other hand, PPARγ antagonist, PD68235, attenuated the blocking effect of RAGE shRNA on the role of AGEs. It

  3. Advanced glycation end products in infant formulas do not contribute to insulin resistance associated with their consumption.

    Directory of Open Access Journals (Sweden)

    Kristína Simon Klenovics

    Full Text Available INTRODUCTION: Infant formula-feeding is associated with reduced insulin sensitivity. In rodents and healthy humans, advanced glycation end product (AGE-rich diets exert diabetogenic effects. In comparison with human breast-milk, infant formulas contain high amounts of AGEs. We assessed the role of AGEs in infant-formula-consumption-associated insulin resistance. METHODS: Total plasma levels of N(ε-(carboxymethyllysine (CML, AGEs-associated fluorescence (λ(ex = 370 nm/λ(em = 445 nm, soluble adhesion molecules, markers of micro- binflammation (hsCRP, oxidative stress (malondialdehyde, 8-isoprostanes and leptinemia were determined, and correlated with insulin sensitivity in a cross-sectional study in 166 healthy term infants aged 3-to-14 months, subdivided according to feeding regimen (breast-milk- vs. infant formula-fed and age (3-to-6-month-olds, 7-to-10-month-olds, and 11-to-14-month-old infants. Effects of the consumption of low- vs. high-CML-containing formulas were assessed. 36 infants aged 5.8 ± 0.3 months were followed-up 7.5 ± 0.3 months later. RESULTS: Cross-sectional study: 3-to-6-month-olds and 7-to-10-month-old formula-fed infants presented higher total plasma CML levels and AGEs-associated fluorescence (p<0.01, both, while only the 3-to-6-month-olds displayed lower insulin sensitivity (p<0.01 than their breast-milk-fed counterparts. 3-to-6-month-olds fed low-CML-containing formulas presented lower total plasma CML levels (p<0.01, but similar insulin sensitivity compared to those on high-CML-containing formulas. Markers of oxidative stress and inflammation, levels of leptin and adhesion molecules did not differ significantly between the groups. Follow-up study: at initial investigation, the breast-milk-consuming infants displayed lower total plasma CML levels (p<0.01 and AGEs-associated fluorescence (p<0.05, but higher insulin sensitivity (p<0.05 than the formulas-consuming infants. At follow-up, the groups did not differ

  4. Activation of Akt by advanced glycation end products (AGEs: involvement of IGF-1 receptor and caveolin-1.

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    Su-Jung Yang

    Full Text Available Diabetes is characterized by chronic hyperglycemia, which in turn facilitates the formation of advanced glycation end products (AGEs. AGEs activate signaling proteins such as Src, Akt and ERK1/2. However, the mechanisms by which AGEs activate these kinases remain unclear. We examined the effect of AGEs on Akt activation in 3T3-L1 preadipocytes. Addition of AGEs to 3T3-L1 cells activated Akt in a dose- and time-dependent manner. The AGEs-stimulated Akt activation was blocked by a PI3-kinase inhibitor LY 294002, Src inhibitor PP2, an antioxidant NAC, superoxide scavenger Tiron, or nicotinamide adenine dinucleotide phosphate (NAD(PH oxidase inhibitor DPI, suggesting the involvement of Src and NAD(PH oxidase in the activation of PI3-kinase-Akt pathway by AGEs. AGEs-stimulated Src tyrosine phosphorylation was inhibited by NAC, suggesting that Src is downstream of NAD(PH oxidase. The AGEs-stimulated Akt activity was sensitive to Insulin-like growth factor 1 receptor (IGF-1R kinase inhibitor AG1024. Furthermore, AGEs induced phosphorylation of IGF-1 receptorβsubunit (IGF-1Rβ on Tyr1135/1136, which was sensitive to PP2, indicating that AGEs stimulate Akt activity by transactivating IGF-1 receptor. In addition, the AGEs-stimulated Akt activation was attenuated by β-methylcyclodextrin that abolishes the structure of caveolae, and by lowering caveolin-1 (Cav-1 levels with siRNAs. Furthermore, addition of AGEs enhanced the interaction of phospho-Cav-1 with IGF-1Rβ and transfection of 3T3-L1 cells with Cav-1 Y14F mutants inhibited the activation of Akt by AGEs. These results suggest that AGEs activate NAD(PH oxidase and Src which in turn phosphorylates IGF-1 receptor and Cav-1 leading to activation of IGF-1 receptor and the downstream Akt in 3T3-L1 cells. AGEs treatment promoted the differentiation of 3T3-L1 preadipocytes and addition of AG1024, LY 294002 or Akt inhibitor attenuated the promoting effect of AGEs on adipogenesis, suggesting that IGF-1

  5. Advanced glycation end products accelerate ischemia/reperfusion injury through receptor of advanced end product/nitrative thioredoxin inactivation in cardiac microvascular endothelial cells.

    Science.gov (United States)

    Liu, Yi; Ma, Yanzhuo; Wang, Rutao; Xia, Chenhai; Zhang, Rongqing; Lian, Kun; Luan, Ronghua; Sun, Lu; Yang, Lu; Lau, Wayne B; Wang, Haichang; Tao, Ling

    2011-10-01

    The advanced glycation end products (AGEs) are associated with increased cardiac endothelial injury. However, no causative link has been established between increased AGEs and enhanced endothelial injury after ischemia/reperfusion. More importantly, the molecular mechanisms by which AGEs may increase endothelial injury remain unknown. Adult rat cardiac microvascular endothelial cells (CMECs) were isolated and incubated with AGE-modified bovine serum albumin (BSA) or BSA. After AGE-BSA or BSA preculture, CMECs were subjected to simulated ischemia (SI)/reperfusion (R). AGE-BSA increased SI/R injury as evidenced by enhanced lactate dehydrogenase release and caspase-3 activity. Moreover, AGE-BSA significantly increased SI/R-induced oxidative/nitrative stress in CMECs (as measured by increased inducible nitric oxide synthase expression, total nitric oxide production, superoxide generation, and peroxynitrite formation) and increased SI/R-induced nitrative inactivation of thioredoxin-1 (Trx-1), an essential cytoprotective molecule. Supplementation of EUK134 (peroxynitrite decomposition catalyst), human Trx-1, or soluble receptor of advanced end product (sRAGE) (a RAGE decoy) in AGE-BSA precultured cells attenuated SI/R-induced oxidative/nitrative stress, reduced SI/R-induced Trx-1 nitration, preserved Trx-1 activity, and reduced SI/R injury. Our results demonstrated that AGEs may increase SI/R-induced endothelial injury by increasing oxidative/nitrative injury and subsequent nitrative inactivation of Trx-1. Interventions blocking RAGE signaling or restoring Trx activity may be novel therapies to mitigate endothelial ischemia/reperfusion injury in the diabetic population.

  6. Advanced glycation end products induce human corneal epithelial cells apoptosis through generation of reactive oxygen species and activation of JNK and p38 MAPK pathways.

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    Long Shi

    Full Text Available Advanced Glycation End Products (AGEs has been implicated in the progression of diabetic keratopathy. However, details regarding their function are not well understood. In the present study, we investigated the effects of intracellular reactive oxygen species (ROS and JNK, p38 MAPK on AGE-modified bovine serum albumin (BSA induced Human telomerase-immortalized corneal epithelial cells (HUCLs apoptosis. We found that AGE-BSA induced HUCLs apoptosis and increased Bax protein expression, decreased Bcl-2 protein expression. AGE-BSA also induced the expression of receptor for advanced glycation end product (RAGE. AGE-BSA-RAGE interaction induced intracellular ROS generation through activated NADPH oxidase and increased the phosphorylation of p47phox. AGE-BSA induced HUCLs apoptosis was inhibited by pretreatment with NADPH oxidase inhibitors, ROS quencher N-acetylcysteine (NAC or neutralizing anti-RAGE antibodies. We also found that AGE-BSA induced JNK and p38 MAPK phosphorylation. JNK and p38 MAPK inhibitor effectively blocked AGE-BSA-induced HUCLs apoptosis. In addition, NAC completely blocked phosphorylation of JNK and p38 MAPK induced by AGE-BSA. Our results indicate that AGE-BSA induced HUCLs apoptosis through generation of intracellular ROS and activation of JNK and p38 MAPK pathways.

  7. Morphological adaptation of muscle collagen and receptor of advanced glycation end product (RAGE) in osteoarthritis patients with 12 weeks of resistance training

    DEFF Research Database (Denmark)

    Mattiello-Sverzut, Ana Claudia; Petersen, Susanne G; Kjaer, Michael

    2013-01-01

    The aim of this study was to investigate the effect of 12-week resistance training on morphological presence of collagen and RAGE (receptor for advanced glycation end products) in skeletal muscle of patients with knee osteoarthritis (OA). Little is known about the influence of exercise on the ske......The aim of this study was to investigate the effect of 12-week resistance training on morphological presence of collagen and RAGE (receptor for advanced glycation end products) in skeletal muscle of patients with knee osteoarthritis (OA). Little is known about the influence of exercise....... The patients (age 55-69 years) were divided into three groups, treated with NSAID, glucosamine or placebo. In addition, the muscle samples were analysed by immunohistochemistry for collagen types, RAGE and capillaries ratio. An increment in immunoreactivity for type IV collagen after the training period...... was observed in 72 % of all biopsies when compared with their respective baseline samples. Reduced immunoreactivity of collagen type I was observed in all patients treated with glucosamine. A significant increase with training in the amount of RAGE was detected in the placebo group only (p ...

  8. Evaluating the extent of protein damage in dairy products: simultaneous determination of early and advanced glycation-induced lysine modifications.

    Science.gov (United States)

    Hegele, Jörg; Parisod, Véronique; Richoz, Janique; Förster, Anke; Maurer, Sarah; Krause, René; Henle, Thomas; Bütler, Timo; Delatour, Thierry

    2008-04-01

    An isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to determine lysine (Lys), N(epsilon)-fructosyllysine (FL), N epsilon-carboxymethyllysine (CML), and pyrraline (Pyr) in dairy products. The presented approach entails protein cleavage via enzymatic digestion to liberate the aforementioned compounds, which were then quantified using a stable isotope dilution assay. LC-MS/MS analysis was performed by positive electrospray ionization recording two transition reactions per analyte in selected reaction monitoring mode. The CML and Lys values obtained with enzymatic digestion were compared to those acquired with acid hydrolysis HCl (6 mol/L), and the two proteolysis methods yielded comparable quantifications. Allowing for the fact that the investigated compounds are formed during different stages of the glycation process, the method is able to reveal the progress of protein glycation in dairy products.

  9. Methylglyoxal mediated conformational changes in histone H2A-generation of carboxyethylated advanced glycation end products.

    Science.gov (United States)

    Mir, Abdul Rouf; uddin, Moin; Alam, Khursheed; Ali, Asif

    2014-08-01

    Methylglyoxal, an oxo-aldehyde has been implicated as a potential precursor in non enzymatic glycation reactions. Its role in the modification of extra cellular proteins has been extensively reported, but little is known about its modification of nuclear proteins, like histones. Here, we report the methylglyoxal induced modification of histone H2A which forms an essential part of intact core nucleosome. In this study commercially available histone H2A was subjected to in vitro non-enzymatic glycation by methylglyoxal. The structural alterations in the histone were characterised by various biophysical and biochemical techniques. The modified histone showed hyperchromicity at 276nm, loss in intrinsic tyrosine fluorescence intensity at 305nm along with a red shift, cross linking and dimer formation in SDS PAGE, induction of α-helix in CD spectroscopy, reduced hydrophobicity in ANS binding studies, accumulation of AGE products, increased carbonyl content, and appearance of a novel peak showing carboxyethylation complemented by a shift in amide I and amide II bands in ATR-FTIR spectroscopy. The modified histone exhibited increased melting temperatures (Tm) and enhanced heat capacities (Cp) in differential scanning calorimetric analysis. The results suggest that methylglyoxal significantly altered the structure of the nuclear histone H2A by non enzymatic glycation reaction. The conformational changes in histone H2A may influence the chromatin integrity which may have implications in various pathological conditions.

  10. Advancement in glycated hemoglobin detection%糖化血红蛋白检测方法研究进展

    Institute of Scientific and Technical Information of China (English)

    汤世博; 曹利民

    2013-01-01

    糖基化红细胞血红蛋白(glycated hemoglobin,GHb)是一种反映糖尿病患者病情的很好的测定指标,在国外已作为糖尿病疗效判定和调整治疗方案的“金指标”.本文对国内外8种GHb的检测方法进行了论述及优缺点的比较,有助于各医院根据自身条件,选择和制定该项目的检测方法.%The percentage of glycated hemoglobin is a good index that can reflect the patient' s condition with diabetes mellitus and has been the “ gold standard" to determine and adjust the treatment schemes for diabetes overseas.In this paper,we discuss eight detection methods for glycated hemoglobin at home and abroad,and compare the advantages and disadvantages of these methods.This paper is helpful for hospitals to choose and establish the detection method according to their own conditions

  11. In skeletal muscle advanced glycation end products (AGEs) inhibit insulin action and induce the formation of multimolecular complexes including the receptor for AGEs.

    Science.gov (United States)

    Cassese, Angela; Esposito, Iolanda; Fiory, Francesca; Barbagallo, Alessia P M; Paturzo, Flora; Mirra, Paola; Ulianich, Luca; Giacco, Ferdinando; Iadicicco, Claudia; Lombardi, Angela; Oriente, Francesco; Van Obberghen, Emmanuel; Beguinot, Francesco; Formisano, Pietro; Miele, Claudia

    2008-12-26

    Chronic hyperglycemia promotes insulin resistance at least in part by increasing the formation of advanced glycation end products (AGEs). We have previously shown that in L6 myotubes human glycated albumin (HGA) induces insulin resistance by activating protein kinase Calpha (PKCalpha). Here we show that HGA-induced PKCalpha activation is mediated by Src. Coprecipitation experiments showed that Src interacts with both the receptor for AGE (RAGE) and PKCalpha in HGA-treated L6 cells. A direct interaction of PKCalpha with Src and insulin receptor substrate-1 (IRS-1) has also been detected. In addition, silencing of IRS-1 expression abolished HGA-induced RAGE-PKCalpha co-precipitation. AGEs were able to induce insulin resistance also in vivo, as insulin tolerance tests revealed a significant impairment of insulin sensitivity in C57/BL6 mice fed a high AGEs diet (HAD). In tibialis muscle of HAD-fed mice, insulin-induced glucose uptake and protein kinase B phosphorylation were reduced. This was paralleled by a 2.5-fold increase in PKCalpha activity. Similarly to in vitro observations, Src phosphorylation was increased in tibialis muscle of HAD-fed mice, and co-precipitation experiments showed that Src interacts with both RAGE and PKCalpha. These results indicate that AGEs impairment of insulin action in the muscle might be mediated by the formation of a multimolecular complex including RAGE/IRS-1/Src and PKCalpha.

  12. The Extract of Litsea japonica Reduced the Development of Diabetic Nephropathy via the Inhibition of Advanced Glycation End Products Accumulation in db/db Mice

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    Eunjin Sohn

    2013-01-01

    Full Text Available Increasing evidence indicates that advanced glycation end products (AGEs contribute to the pathogenesis of diabetic nephropathy. The aim of this study was to investigate the protective effect of L. japonica extract (LJE against renal damage in the db/db mouse. LJE (100 or 250 mg/kg per day was given to diabetic mice for 12 weeks. Body weight, blood glucose levels, glycated hemoglobin (HbA1c levels, and proteinuria were examined. In in vitro assay of the inhibition of AGE formation, immunohistochemical analysis of podocyte loss and AGE accumulations were performed. In 20-week-old db/db mice, severe hyperglycemia developed, and proteinuria was significantly increased. Diabetes induced markedly morphological alterations to the renal glomerular cells. AGE accumulations and podocyte loss were detected in renal glomeruli. LJE treatment significantly reduced proteinuria and AGE accumulations in diabetic mice. Moreover, the loss of nephrin, an important slit diaphragm component in the kidneys, was restored by LJE treatment. Our studies suggest that LJE might be beneficial for the treatment of diabetic nephropathy. The ability of LJE to attenuate proteinuria and podocyte dysfunction may be mediated by the inhibition of AGE accumulation in the context of diabetic nephropathy in db/db mice.

  13. Plasma Proteins Modified by Advanced Glycation End Products (AGEs) Reveal Site-specific Susceptibilities to Glycemic Control in Patients with Type 2 Diabetes.

    Science.gov (United States)

    Greifenhagen, Uta; Frolov, Andrej; Blüher, Matthias; Hoffmann, Ralf

    2016-04-29

    Protein glycation refers to the reversible reaction between aldoses (or ketoses) and amino groups yielding relatively stable Amadori (or Heyns) products. Consecutive oxidative cleavage reactions of these products or the reaction of amino groups with other reactive substances (e.g. α-dicarbonyls) yield advanced glycation end products (AGEs) that can alter the structures and functions of proteins. AGEs have been identified in all organisms, and their contents appear to rise with some diseases, such as diabetes and obesity. Here, we report a pilot study using highly sensitive and specific proteomics approach to identify and quantify AGE modification sites in plasma proteins by reversed phase HPLC mass spectrometry in tryptic plasma digests. In total, 19 AGE modification sites corresponding to 11 proteins were identified in patients with type 2 diabetes mellitus under poor glycemic control. The modification degrees of 15 modification sites did not differ among cohorts of normoglycemic lean or obese and type 2 diabetes mellitus patients under good and poor glycemic control. The contents of two amide-AGEs in human serum albumin and apolipoprotein A-II were significantly higher in patients with poor glycemic control, although the plasma levels of both proteins were similar among all plasma samples. These two modification sites might be useful to predict long term, AGE-related complications in diabetic patients, such as impaired vision, increased arterial stiffness, or decreased kidney function.

  14. Effect of PKC-β Signaling Pathway on Expression of MCP-1 and VCAM-1 in Different Cell Models in Response to Advanced Glycation End Products (AGEs).

    Science.gov (United States)

    Rempel, Lisienny C T; Finco, Alessandra B; Maciel, Rayana A P; Bosquetti, Bruna; Alvarenga, Larissa M; Souza, Wesley M; Pecoits-Filho, Roberto; Stinghen, Andréa E M

    2015-05-14

    Advanced glycation end products (AGEs) are compounds classified as uremic toxins in patients with chronic kidney disease that have several pro-inflammatory effects and are implicated in the development of cardiovascular diseases. To explore the mechanisms of AGEs-endothelium interactions through the receptor for AGEs (RAGE) in the PKC-β pathway, we evaluated the production of MCP-1 and VCAM-1 in human endothelial cells (HUVECs), monocytes, and a coculture of both. AGEs were prepared by albumin glycation and characterized by absorbance and electrophoresis. The effect of AGEs on cell viability was assessed with an MTT assay. The cells were also treated with AGEs with and without a PKC-β inhibitor. MCP-1 and VCAM-1 in the cell supernatants were estimated by ELISA, and RAGE was evaluated by immunocytochemistry. AGEs exposure did not affect cell viability, but AGEs induced RAGE, MCP-1, and VCAM-1 expression in HUVECs. When HUVECs or monocytes were incubated with AGEs and a PKC-β inhibitor, MCP-1 and VCAM-1 expression significantly decreased. However, in the coculture, exposure to AGEs and a PKC-β inhibitor produced no significant effect. This study demonstrates, in vitro, the regulatory mechanisms involved in MCP-1 production in three cellular models and VCAM-1 production in HUVECs, and thus mimics the endothelial dysfunction caused by AGEs in early atherosclerosis. Such mechanisms could serve as therapeutic targets to reduce the harmful effects of AGEs in patients with chronic kidney disease.

  15. Diverging effects of diabetes mellitus in patients with peripheral artery disease and abdominal aortic aneurysm and the role of advanced glycation end products: : ARTERY study. Protocol for a multicenter cross-sectional study

    NARCIS (Netherlands)

    de Vos, L.C.; Boersema, J.; Hillebrands, J.L.; Schalkwijk, C.G.; Meerwaldt, R.; Breek, J.C.; Smit, A. J.; Zeebregts, C. J.; Lefrandt, J.D.

    2016-01-01

    Introduction: Diabetes mellitus is a well-defined risk factor for peripheral artery disease (PAD), but protects against the development and growth of abdominal aortic aneurysm (AAA). Diabetes mellitus is associated with arterial stiffening and peripheral arterial media sclerosis. Advanced glycation

  16. Irbesartan treatment does not influence plasma levels of the advanced glycation end products N(epsilon)(1-carboxymethyl)lysine and N(epsilon)(1-carboxyethyl)lysine in patients with type 2 diabetes and microalbuminuria. A randomized controlled trial

    DEFF Research Database (Denmark)

    Engelen, Lian; Persson, Frederik; Ferreira, Isabel;

    2011-01-01

    BACKGROUND: In vitro and animal experiments have shown inhibiting effects of angiotensin receptor blockers (ARBs) on the formation of advanced glycation end products (AGEs), which are known to be involved in the development of cardiovascular complications in diabetes. However, sufficient human data...

  17. Iridoids are natural glycation inhibitors.

    Science.gov (United States)

    West, Brett J; Deng, Shixin; Uwaya, Akemi; Isami, Fumiyuki; Abe, Yumi; Yamagishi, Sho-Ichi; Jensen, C Jarakae

    2016-08-01

    Glycation of amino acid residues in proteins leads to the eventual formation of advanced glycation end products (AGEs). AGE formation significantly influences human health and the aging process. AGE accumulation rates may be slowed by modifications to lifestyle or by pharmacological strategies. But the use of therapeutic drugs is not an appropriate means of controlling AGEs within the general population. However, phytochemical constituents in plant-based foods exhibit anti-glycation activities and may be more appropriate for general consumption. Among these phytochemicals are iridoids. The anti-AGE potential of iridoids has been demonstrated in vitro and in vivo, while also revealing possible mechanisms of action. Inclusion of iridoid food sources in the diet may be a useful component of strategies intended to mitigate AGE accumulation within the body.

  18. N-phenacylthiazolium bromide reduces bone fragility induced by nonenzymatic glycation.

    Directory of Open Access Journals (Sweden)

    Brian S Bradke

    Full Text Available Nonenzymatic glycation (NEG describes a series of post-translational modifications in the collagenous matrices of human tissues. These modifications, known as advanced glycation end-products (AGEs, result in an altered collagen crosslink profile which impacts the mechanical behavior of their constituent tissues. Bone, which has an organic phase consisting primarily of type I collagen, is significantly affected by NEG. Through constant remodeling by chemical resorption, deposition and mineralization, healthy bone naturally eliminates these impurities. Because bone remodeling slows with age, AGEs accumulate at a greater rate. An inverse correlation between AGE content and material-level properties, particularly in the post-yield region of deformation, has been observed and verified. Interested in reversing the negative effects of NEG, here we evaluate the ability of n-phenacylthiazolium bromide (PTB to cleave AGE crosslinks in human cancellous bone. Cancellous bone cylinders were obtained from nine male donors, ages nineteen to eighty, and subjected to one of six PTB treatments. Following treatment, each specimen was mechanically tested under physiological conditions to failure and AGEs were quantified by fluorescence. Treatment with PTB showed a significant decrease in AGE content versus control NEG groups as well as a significant rebound in the post-yield material level properties (p<0.05. The data suggest that treatment with PTB could be an effective means to reduce AGE content and decrease bone fragility caused by NEG in human bone.

  19. Inhibition of Advanced Glycation End Products (AGEs Accumulation by Pyridoxamine Modulates Glomerular and Mesangial Cell Estrogen Receptor α Expression in Aged Female Mice.

    Directory of Open Access Journals (Sweden)

    Simone Pereira-Simon

    Full Text Available Age-related increases in oxidant stress (OS play a role in regulation of estrogen receptor (ER expression in the kidneys. In this study, we establish that in vivo 17β-estradiol (E2 replacement can no longer upregulate glomerular ER expression by 21 months of age in female mice (anestrous. We hypothesized that advanced glycation end product (AGE accumulation, an important source of oxidant stress, contributes to these glomerular ER expression alterations. We treated 19-month old ovariectomized female mice with pyridoxamine (Pyr, a potent AGE inhibitor, in the presence or absence of E2 replacement. Glomerular ERα mRNA expression was upregulated in mice treated with both Pyr and E2 replacement and TGFβ mRNA expression decreased compared to controls. Histological sections of kidneys demonstrated decreased type IV collagen deposition in mice receiving Pyr and E2 compared to placebo control mice. In addition, anti-AGE defenses Sirtuin1 (SIRT1 and advanced glycation receptor 1 (AGER1 were also upregulated in glomeruli following treatment with Pyr and E2. Mesangial cells isolated from all groups of mice demonstrated similar ERα, SIRT1, and AGER1 expression changes to those of whole glomeruli. To demonstrate that AGE accumulation contributes to the observed age-related changes in the glomeruli of aged female mice, we treated mesangial cells from young female mice with AGE-BSA and found similar downregulation of ERα, SIRT1, and AGER1 expression. These results suggest that inhibition of intracellular AGE accumulation with pyridoxamine may protect glomeruli against age-related oxidant stress by preventing an increase of TGFβ production and by regulation of the estrogen receptor.

  20. Caffeoylated phenylpropanoid glycosides from Brandisia hancei inhibit advanced glycation end product formation and aldose reductase in vitro and vessel dilation in larval zebrafish in vivo.

    Science.gov (United States)

    Yu, Song Yi; Lee, Ik-Soo; Jung, Seung-Hyun; Lee, Yun Mi; Lee, Yu-Ri; Kim, Joo-Hwan; Sun, Hang; Kim, Jin Sook

    2013-12-01

    In our continuing efforts to identify effective naturally sourced agents for diabetic complications, five caffeoylated phenylpropanoid glycosides, acteoside (1), isoacteoside (2), poliumoside (3), brandioside (4), and pheliposide (5) were isolated from the 80% EtOH extract of Brandisia hancei stems and leaves. These isolates (1-5) were subjected to an in vitro bioassay evaluating their inhibitory activity on advanced glycation end product formation and rat lens aldose reductase activity. All tested compounds exhibited significant inhibition of advanced glycation end product formation with IC50 values of 4.6-25.7 µM, compared with those of aminoguanidine (IC50=1,056 µM) and quercetin (IC50=28.4 µM) as positive controls. In the rat lens aldose reductase assay, acteoside, isoacteoside, and poliumoside exhibited greater inhibitory effects on rat lens aldose reductase with IC50 values of 0.83, 0.83, and 0.85 µM, respectively, than those of the positive controls, 3,3-tetramethyleneglutaric acid (IC50=4.03 µM) and quercetin (IC50=7.2 µM). In addition, the effect of acteoside on the dilation of hyaloid-retinal vessels induced by high glucose in larval zebrafish was investigated. Acteoside reduced the diameters of high glucose-induced hyaloid-retinal vessels by 69% at 10 µM and 81% at 20 µM, compared to the high glucose-treated control group. These results suggest that B. hancei and its active components might be beneficial in the treatment and prevention of diabetic vascular complications.

  1. C-reactive protein, advanced glycation end products and their receptor in type 2 diabetic, elderly patients with mild cognitive impairment

    Directory of Open Access Journals (Sweden)

    Malgorzata eGorska-Ciebiada

    2015-10-01

    Full Text Available Objective: The aim of the study was to evaluate serum levels of AGEs (advanced glycation end products, RAGE (receptor for advanced glycation end products and CRP (C-reactive protein in elderly patients with T2DM with and without mild cognitive impairment (MCI and to determine the predictors (including AGEs, RAGE and CRP levels of having MCI in elderly patients with type 2 diabetes.Methods: 276 diabetics elders were screened for MCI (using the Montreal Cognitive Assessment: MoCA score. Data of biochemical parameters and biomarkers were collected. Results: Serum AGEs, RAGE and CRP levels were significantly increased in MCI patients compared to controls. In group of patients with MCI serum RAGE level was positively correlated with AGEs level and with CRP level. RAGE, AGEs and CRP concentrations were positively correlated with HbA1c levels and negatively correlated with MoCA score. The univariate logistic regression models revealed that variables which increased the likelihood of diagnosis of MCI in elderly patients with type 2 diabetes were: higher levels of HbA1c, RAGE, AGEs, CRP, TG, lower level of HDL cholesterol, previous CVD, HA or use of HA drugs, hiperlipidaemia, retinopathy, nephropathy, increased number of co-morbidities, older age and less years of formal education. HA or use of HA drugs, previous CVD, higher level of RAGE and CRP, older age and less years of formal education are the factors increasing the likelihood of having MCI in elderly patients with type 2 diabetes in multivariable model. Conclusions: In summary, serum AGEs, RAGE and CRP are increased in the circulation of MCI elderly diabetic patients compared to controls. A larger population-based prospective study needs to be performed to further confirm the relationship between AGEs, RAGE and the cognitive decline or progress to dementia.

  2. 渐进性糖化终产物与糖尿病肾病%Relationship of advanced glycation end products and diabetic nephropathy

    Institute of Scientific and Technical Information of China (English)

    周雪梅; 王伯初; 祝连彩; 杨宪

    2011-01-01

    高级糖化终末产物(advanced glycation end product,AGE)参与了糖尿病、动脉粥样硬化、癌症等多种疾病的发生和发展,尤其是其导致的糖尿病肾病(diabetic nephropathy,DN)是终末期肾竭竭的主要病因,因此探索以AGEs为靶点的DN治疗手段成为了国内外研究的热点.本文概述了国内外关于AGE参与DN的发病机制,靶向AGE的DN治疗策略,以及天然中药基于AGE为靶点干预DN的研究进展,初步探讨了靶向AGE的DN天然药物的筛选模型.%Advanced glycation end products (AGEs) are incriminated in the genesis and development of various diseases, such as diabetes, arteriosclerosis, cancer, etc. Especially, it plays a central role in the pathogenesis of diabetic nephropathy, a leading cause of end-stage renal disease. So, increasing attention has been paid to explore the treatment strategies of diabetic nephropathy based on AGEs. In this paper, we mainly reviewed the involvement of AGEs in the pathogenesis of diabetic nephropathy, AGEs-targeted treatment strategies of diabetic nephropathy, and research progress of AGEs-targeted interference in diabetic nephropathy by natural medicine. Furthermore, the screening model of natural medicine for diabetic nephropathy with AGEs as a target was discussed.

  3. Advanced glycation end products inhibit both infection and transmission in trans of HIV-1 from monocyte-derived dendritic cells to autologous T cells.

    Science.gov (United States)

    Nasreddine, Nadine; Borde, Chloé; Gozlan, Joël; Bélec, Laurent; Maréchal, Vincent; Hocini, Hakim

    2011-05-15

    Highly active antiretroviral therapy is associated with carbohydrate metabolic alterations that may lead to diabetes. One consequence of hyperglycemia is the formation of advanced glycation end products (AGEs) that are involved in diabetes complications. We investigated the impact of AGEs on the infection of monocyte-derived dendritic cells (MDDCs) by HIV-1 and the ability of MDDCs to transmit the virus to T cells. We showed that AGEs could inhibit infection of MDDCs with primary R5-tropic HIV-1(Ba-L) by up to 85 ± 9.2% and with primary X4-tropic HIV-1(VN44) by up to 60 ± 8.5%. This inhibitory effect of AGEs was not prevented by a neutralizing anti-receptor for advanced glycation end products (anti-RAGE) Ab, demonstrating a RAGE-independent mechanism. Moreover, AGEs inhibited by 70-80% the transmission in trans of the virus to CD4 T cells. Despite the inhibitory effect of AGEs on both MDDC infection and virus transmission in trans, no inhibition of virus attachment to cell membrane was observed, confirming that attachment and transmission of the virus involve independent mechanisms. The inhibitory effect of AGEs on infection was associated with a RAGE-independent downregulation of CD4 at the cell membrane and by a RAGE-dependent repression of the CXCR4 and CCR5 HIV-1 receptors. AGEs induce the secretion of proinflammatory cytokines IL-6, TNF-α, and IL-12, but not RANTES or MIP-1α, and did not lead to MDDC maturation as demonstrated by the lack of expression of the CD83 molecule. Taken together, our results suggest that AGEs can play an inhibiting role in HIV-1 infection in patients who accumulate circulating AGEs, including patients treated with protease inhibitors that developed diabetes.

  4. Gramicidin S: a peptide model for protein glycation and reversal of glycation using nucleophilic amines.

    Science.gov (United States)

    Shakkottai, V G; Sudha, R; Balaram, P

    2002-08-01

    Nonenzymatic glycation of proteins has been implicated in various diabetic complications and age-related disorders. Proteins undergo glycation at the N-terminus or at the epsilon-amino group of lysine residues. Glycation of proteins proceeds through the stages of Schiff base formation, conversion to ketoamine product and advanced glycation end products. Gramicidin S, which has two ornithine residues, was used as a model system to study the various stages of glycation of proteins using electrospray ionization mass spectrometry. The proximity of two ornithine residues in the peptide favors the glycation reaction. Formation of advanced glycation end products and diglycation on ornithine residues in gramicidin S were observed. The formation of Schiff base adduct is reversible, whereas the Amadori rearrangement to the ketoamine product is irreversible. Nucleophilic amines and hydrazines can deglycate the Schiff base adduct of glucose with peptides and proteins. Hydroxylamine, isonicotinic acid hydrazide and aminoguanidine effectively removed glucose from the Schiff base adduct of gramicidin S. Hydroxylamine is more effective in deglycating the adduct compared with isonicotinic acid hydrazide and aminoguanidine. The observation that the hydrazines are effective in deglycating the Schiff base adduct even in the presence of high concentrations of glucose, may have a possible therapeutic application in preventing complications of diabetes mellitus. Hydrazines may be used to distinguish between the Schiff base and the ketoamine products formed at the initial stages of glycation.

  5. A capture method based on the VC1 domain reveals new binding properties of the human receptor for advanced glycation end products (RAGE

    Directory of Open Access Journals (Sweden)

    Genny Degani

    2017-04-01

    Full Text Available The Advanced Glycation and Lipoxidation End products (AGEs and ALEs are a heterogeneous class of compounds derived from the non-enzymatic glycation or protein adduction by lipoxidation break-down products. The receptor for AGEs (RAGE is involved in the progression of chronic diseases based on persistent inflammatory state and oxidative stress. RAGE is a pattern recognition receptor (PRR and the inhibition of the interaction with its ligands or of the ligand accumulation have a potential therapeutic effect. The N-terminal domain of RAGE, the V domain, is the major site of AGEs binding and is stabilized by the adjacent C1 domain. In this study, we set up an affinity assay relying on the extremely specific biological interaction AGEs ligands have for the VC1 domain. A glycosylated form of VC1, produced in the yeast Pichia pastoris, was attached to magnetic beads and used as insoluble affinity matrix (VC1-resin. The VC1 interaction assay was employed to isolate specific VC1 binding partners from in vitro generated AGE-albumins and modifications were identified/localized by mass spectrometry analysis. Interestingly, this method also led to the isolation of ALEs produced by malondialdehyde treatment of albumins. Computational studies provided a rational-based interpretation of the contacts established by specific modified residues and amino acids of the V domain. The validation of VC1-resin in capturing AGE-albumins from complex biological mixtures such as plasma and milk, may lead to the identification of new RAGE ligands potentially involved in pro-inflammatory and pro-fibrotic responses, independently of their structures or physical properties, and without the use of any covalent derivatization process. In addition, the method can be applied to the identification of antagonists of RAGE-ligand interaction.

  6. Crosstalk between advanced glycation end products (AGEs)-receptor RAGE axis and dipeptidyl peptidase-4-incretin system in diabetic vascular complications.

    Science.gov (United States)

    Yamagishi, Sho-ichi; Fukami, Kei; Matsui, Takanori

    2015-01-13

    Advanced glycation end products (AGEs) consist of heterogenous group of macroprotein derivatives, which are formed by non-enzymatic reaction between reducing sugars and amino groups of proteins, lipids and nucleic acids, and whose process has progressed at an accelerated rate under diabetes. Non-enzymatic glycation and cross-linking of protein alter its structural integrity and function, contributing to the aging of macromolecules. Furthermore, engagement of receptor for AGEs (RAGE) with AGEs elicits oxidative stress generation and subsequently evokes proliferative, inflammatory, and fibrotic reactions in a variety of cells. Indeed, accumulating evidence has suggested the active involvement of accumulation of AGEs in diabetes-associated disorders such as diabetic microangiopathy, atherosclerotic cardiovascular diseases, Alzheimer's disease and osteoporosis. Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are incretins, gut hormones secreted from the intestine in response to food intake, both of which augment glucose-induced insulin release, suppress glucagon secretion, and slow gastric emptying. Since GLP-1 and GIP are rapidly degraded and inactivated by dipeptidyl peptidase-4 (DPP-4), inhibition of DPP-4 and/or DPP-4-resistant GLP-1 analogues have been proposed as a potential target for the treatment of diabetes. Recently, DPP-4 has been shown to cleave multiple peptides, and blockade of DPP-4 could exert diverse biological actions in GLP-1- or GIP-independent manner. This article summarizes the crosstalk between AGEs-RAGE axis and DPP-4-incretin system in the development and progression of diabetes-associated disorders and its therapeutic intervention, especially focusing on diabetic vascular complications.

  7. Inhibition of glucose- and fructose-mediated protein glycation by infusions and ethanolic extracts of ten culinary herbs and spices

    Directory of Open Access Journals (Sweden)

    Jugjeet Singh Ramkissoon

    2016-06-01

    Conclusions: The higher rate of fluorescence generation by fructation suggests that glycation by fructose deserves much attention as a glycating agent. Data herein showed that the extracts inhibited GMG and FMG. Thus, these edible plants could be a natural source of antioxidants and anti-glycation agent for preventing advanced glycation end-products-mediated complications.

  8. Precursor of advanced glycation end products mediates ER-stress-induced caspase-3 activation of human dermal fibroblasts through NAD(PH oxidase 4.

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    Danielle T Loughlin

    Full Text Available BACKGROUND: The precursor for advanced glycation end products, 3-deoxyglucosone (3DG is highly upregulated in skin explants of diabetic cutaneous wounds, and has been shown to negatively impact dermal fibroblasts, which are crucial in wound remodeling. 3DG induces apoptosis however; the mechanisms involved in the apoptotic action of 3DG in the pathogenesis of diabetic chronic wounds are poorly understood. Therefore, we sought to delineate novel mechanisms involved with the 3DG-collagen induced apoptosis. METHODOLOGY/PRINCIPAL FINDINGS: Using human dermal fibroblasts, we demonstrated that 3DG-modified collagen induces oxidative stress and caspase-3 activation. Oxidative stress was found to be dependent on the upregulation of NAD(PH oxidase 4 (Nox4, a reactive oxygen species (ROS Nox homologue, triggering endoplasmic reticulum (ER stress, as assessed by the ER stress-induced apoptosis marker Growth Arrest and DNA Damage-inducible gene 153 (GADD153. We demonstrated that 3DG-collagen activated GADD153 via phosphorylation of p38 mitogen activated protein kinase (MAPK, and this was dependent on upstream ROS. Inhibition of ROS and/or p38 MAPK abrogated 3DG-collagen induced caspase-3 activation. Our investigations also demonstrated that 3DG-collagen-induced caspase-3 activation did not signal through the canonical receptor for advanced glycation end products (RAGE but through integrin alpha1beta1. To further verify the role of integrins, neutralization of integrins alpha1beta1 prevented 3DG-collagen-induced upregulation of ROS, GADD153, and caspase-3 activation; suggesting that 3DG-collagen signaling to the fibroblast is dependent on integrins alpha1beta1. CONCLUSIONS/SIGNIFICANCE: Taken together, these findings demonstrate for the first time that a RAGE independent mechanism is involved in 3DG-collagen-induced apoptosis. Moreover, the ER stress pathway through activation of Nox4 by integrins alpha1beta1 plays a key role in 3DG-collagen-induced caspase

  9. 晚期糖基化终产物对C57小鼠耳蜗螺旋神经节细胞凋亡及其受体表达的影响%Effect of advanced glycation end products on apoptosis of C57 mouse spiral ganglion cells and mRNA expression of advanced glycation end products receptor

    Institute of Scientific and Technical Information of China (English)

    龚麒麟; 左文静; 吴小波; 林昶

    2016-01-01

    目的:研究晚期糖基化终产物(advanced glycation end products,AGEs)对体外培养的小鼠耳蜗螺旋神经节细胞(spiral ganglion cells,SGCs)凋亡及晚期糖基化终产物受体(receptor for advanced glycation end products,RAGE)表达的影响,探讨AGEs诱导SGCs凋亡的可能作用途径,分析神经型老年性聋的可能致病机制。方法运用Tunel法,采用荧光显微镜观察不同浓度、不同时间AGEs对培养的SGCs凋亡的影响,同时用Real time RT-PCR方法检测RAGEmRNA表达。结果AGEs加入细胞培养中,可明显诱导SGCs凋亡,凋亡率与剂量、时间呈正相关。发生凋亡的同时有RAGEmRNA表达增强。结论AGEs对SGCs有诱导凋亡的作用,该作用可能通过RAGE介导。AGEs促使SGCs凋亡可能是神经型老年性聋的发病机制之一。%OBJECTIVE To analyze the effect of advanced glycation end products(AGEs) on apoptosis of cultured mouse spiral ganglion cells(SGCs) and expression of receptor of AGEs(RAGE). To explore the pathway of AGEs in promoting apoptosis of SGCs. And to explore the possible mechanism of neural presbycusis. METHODS The effect of AGEs on apoptosis of SGCs was studied by Tunel technique and fluorescence microscope. The expression of RAGE mRNA was assayed by Real time RT-PCR. RESULTS AGEs induced apoptosis of cultured SGCs. The effects were dose-dependent and time-dependent. Meanwhile RAGE mRNA expression was enhanced in apoptosis cells. CONCLUSION AGEs induced apoptosis in SGCs,which may be mediated by RAGE. And this may be one of the mechanisms of neural presbycusis.

  10. Diverging effects of diabetes mellitus in patients with peripheral artery disease and abdominal aortic aneurysm and the role of advanced glycation end products:: ARTERY study. Protocol for a multicenter cross-sectional study

    OpenAIRE

    Vos, L.C. de; Boersema, J.; Hillebrands, J. L.; Schalkwijk, C. G.; Meerwaldt, R.; Breek, J.C.; Smit, A. J.; C. J. Zeebregts; Lefrandt, J.D.

    2016-01-01

    Introduction: Diabetes mellitus is a well-defined risk factor for peripheral artery disease (PAD), but protects against the development and growth of abdominal aortic aneurysm (AAA). Diabetes mellitus is associated with arterial stiffening and peripheral arterial media sclerosis. Advanced glycation end products (AGEs) are increased in diabetes mellitus and cardiovascular disease. AGEs are known to form cross-links between proteins and are associated with arterial stiffness. Whether AGEs contr...

  11. The Effect of a Phaseolus vulgaris and Dietary Fiber Based Supplement on Advanced Glycation End Products: An Open-label Trial

    Directory of Open Access Journals (Sweden)

    Brett J. West

    2015-07-01

    Full Text Available Elevated Advanced Glycation End product (AGE levels are associated with certain impaired health states. As these are disruptive to the function of healthy tissues, due to their protein cross-linking ability, AGEs are significant contributors to the aging process. In fact, population studies have revealed that AGE levels tend to increase as we get older. Certain lifestyle and dietary factors may accelerate AGE accumulation. Therefore, strategies intended to modify these factors, or mitigate their effects, may be useful in controlling the aging process. In an 11 week open-label clinical trial, 30 adult volunteers consumed daily a commercially available combination of white kidney bean extract, dietary fibers, &beta-carotene and noni (Morinda citrifolia fruit pulp, in combination with calorie restriction and exercise. During the course of the trial, participants experienced significant weekly declines in average body weight and fat mass. The average AGE score, as measured by skin auto-fluorescence, had also decreased significantly. In terms of AGE associated years, the change in AGE scores corresponded to an average decrease of 8.83 years. The results indicate that the intervention contributed to improved health and exhibited anti-aging properties.

  12. Morroniside and loganin extracted from Cornus officinalis have protective effects on rat mesangial cell proliferation exposed to advanced glycation end products by preventing oxidative stress.

    Science.gov (United States)

    Xu, Huiqin; Shen, Jian; Liu, Hong; Shi, Yan; Li, Lihua; Wei, Min

    2006-12-01

    Advanced glycation end products (AGE) are involved in the alterations of renal mesangial cell (MCs) growth, a feature of early stages of diabetic nephropathy (DN). We postulate that morroniside and loganin, 2 components extracted from Cornus officinalis, may ameliorate the detrimental effects of AGE-induced MCs proliferation by preventing oxidative stress. Rat MCs cultured in AGE milieu were treated with morroniside and loganin. Results showed that morroniside and loganin inhibited AGE-induced MC proliferation as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Fluorescence microscopy revealed that the morroniside and loganin improved the morphological changes of MCs. Flow cytometric analysis showed that morroniside and loganin inhibited the cell cycle of rat MCs. Furthermore, the level of reactive oxygen species was significantly reduced, and the activities of superoxide dismutase and glutathione peroxidase were markedly increased, whereas the level of malondialdehyde was not significantly reduced. These results suggest that morroniside and loganin regulate MC growth by preventing oxidative stress. Thus, this study provides a molecular basis for the use of morroniside and loganin in the early stages of DN.

  13. Advanced glycation end product-induced astrocytic differentiation of cultured neurospheres through inhibition of Notch-Hes1 pathway-mediated neurogenesis.

    Science.gov (United States)

    Guo, Yijing; Wang, Pin; Sun, Haixia; Cai, Rongrong; Xia, Wenqing; Wang, Shaohua

    2014-01-01

    This study aims to investigate the roles of the Notch-Hes1 pathway in the advanced glycation end product (AGE)-mediated differentiation of neural stem cells (NSCs). We prepared pLentiLox3.7 lentiviral vectors that express short hairpin RNA (shRNA) against Notch1 and transfected it into NSCs. Cell differentiation was analyzed under confocal laser-scanning microscopy. The percentage of neurons and astrocytes was quantified by normalizing the total number of TUJ1+ (Neuron-specific class III β-tubulin) and GFAP+ (Glial fibrillary acidic protein) cells to the total number of Hoechst 33342-labeled cell nuclei. The protein and gene expression of Notch-Hes1 pathway components was examined via western blot analysis and real-time PCR. After 1 week of incubation, we found that AGE-bovine serum albumin (BSA) (400 μg/mL) induced the astrocytic differentiation of cultured neurospheres and inhibited neuronal formation. The expression of Notch-Hes1 pathway components was upregulated in the cells in the AGE-BSA culture medium. Immunoblot analysis indicated that shRNA silencing of Notch1 expression in NSCs significantly increases neurogenesis and suppresses astrocytic differentiation in NSCs incubated with AGE-BSA. AGEs promote the astrocytic differentiation of cultured neurospheres by inhibiting neurogenesis through the Notch-Hes1 pathway, providing a potential therapeutic target for hyperglycemia-related cognitive deficits.

  14. Comparative effects of pioglitazone and rosiglitazone on plasma levels of soluble receptor for advanced glycation end products in type 2 diabetes mellitus patients.

    Science.gov (United States)

    Oz Gul, Ozen; Tuncel, Ercan; Yilmaz, Yusuf; Ulukaya, Engin; Gul, Cuma Bulent; Kiyici, Sinem; Oral, Arzu Yilmaztepe; Guclu, Metin; Ersoy, Canan; Imamoglu, Sazi

    2010-01-01

    Low levels of soluble receptor for advanced glycation end products (sRAGE) have been associated with the occurrence of vascular complications in patients with type 2 diabetes mellitus. Preliminary evidence has suggested that thiazolidinediones have the ability to modulate circulating levels of this molecule in the hyperglycemic milieu. The aim of this pilot study was to assess the differential effect of 2 different thiazolidinediones-pioglitazone and rosiglitazone-on plasma levels of sRAGE in type 2 diabetes mellitus patients. Sixty type 2 diabetes mellitus subjects were randomly assigned to receive pioglitazone (30 mg/d, n = 19), rosiglitazone (4 mg/d, n = 20), or placebo (medical nutrition therapy, n = 21) for 12 weeks. Changes in plasma glucose, glycosylated hemoglobin, insulin resistance (homeostasis model assessment), total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, and sRAGE were evaluated at baseline and after 12 weeks. At 12 weeks, the pioglitazone (P diabetes mellitus patients, pioglitazone-but not rosiglitazone-significantly raised sRAGE, which may contribute to its antiatherogenic effects.

  15. ER stress is associated with reduced ABCA-1 protein levels in macrophages treated with advanced glycated albumin - reversal by a chemical chaperone.

    Science.gov (United States)

    Castilho, Gabriela; Okuda, Ligia S; Pinto, Raphael S; Iborra, Rodgiro T; Nakandakare, Edna R; Santos, Celio X; Laurindo, Francisco R; Passarelli, Marisa

    2012-07-01

    ATP-binding cassette transporter A1 mediates the export of excess cholesterol from macrophages, contributing to the prevention of atherosclerosis. Advanced glycated albumin (AGE-alb) is prevalent in diabetes mellitus and is associated with the development of atherosclerosis. Independently of changes in ABCA-1 mRNA levels, AGE-alb induces oxidative stress and reduces ABCA-1 protein levels, which leads to macrophage lipid accumulation. These metabolic conditions are known to elicit endoplasmic reticulum (ER) stress. We sought to determine if AGE-alb induces ER stress and unfolded protein response (UPR) in macrophages and how disturbances to the ER could affect ABCA-1 content and cholesterol efflux in macrophages. AGE-alb induced a time-dependent increase in ER stress and UPR markers. ABCA-1 content and cellular cholesterol efflux were reduced by 33% and 47%, respectively, in macrophages treated with AGE-alb, and both were restored by treatment with 4-phenyl butyric acid (a chemical chaperone that alleviates ER stress), but not MG132 (a proteasome inhibitor). Tunicamycin, a classical ER stress inductor, also impaired ABCA-1 expression and cholesterol efflux (showing a decrease of 61% and 82%, respectively), confirming the deleterious effect of ER stress in macrophage cholesterol accumulation. Glycoxidation induces macrophage ER stress, which relates to the reduction in ABCA-1 and in reverse cholesterol transport, endorsing the adverse effect of macrophage ER stress in atherosclerosis. Thus, chemical chaperones that alleviate ER stress may represent a useful tool for the prevention and treatment of atherosclerosis in diabetes.

  16. Receptor for advanced glycation end products plays a more important role in cellular survival than in neurite outgrowth during retinoic acid-induced differentiation of neuroblastoma cells.

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    Sajithlal, Gangadharan; Huttunen, Henri; Rauvala, Heikki; Munch, Gerald

    2002-03-01

    The receptor for advanced glycation end products (RAGE), a member of the immunoglobulin superfamily, is known to interact with amphoterin. This interaction has been proposed to play a role in neurite outgrowth and process elongation during neurodifferentiation. However, there is as yet no direct evidence of the relevance of this pathway to neurodifferentiation under physiological conditions. In this study we have investigated a possible role of RAGE and amphoterin in the retinoic acid-induced differentiation of neuroblastoma cells. The functional inactivation of RAGE by dominant negative and antisense strategies showed that RAGE is not required for process outgrowth or differentiation, although overexpression of RAGE accelerates the elongation of neuritic processes. Using the antisense strategy, amphoterin was shown to be essential for process outgrowth and differentiation, suggesting that amphoterin may interact with other molecules to exert its effect in this context. Interestingly, the survival of the neuroblastoma cells treated with retinoic acid was partly dependent on the expression of RAGE, and inhibition of RAGE function partially blocked the increase in anti-apoptotic protein Bcl-2 following retinoic acid treatment. Based on these results we propose that a combination therapy using RAGE blockers and retinoic acid may prove as a useful approach for chemotherapy for the treatment of neuroblastoma.

  17. Advanced Glycation End Products Induce Endothelial-to-Mesenchymal Transition via Downregulating Sirt 1 and Upregulating TGF-β in Human Endothelial Cells

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    Wei He

    2015-01-01

    Full Text Available In the present study, we examined the advanced glycation end products- (AGEs- induced endothelial-to-mesenchymal transition (EndMT in human umbilical vein endothelial cells (HUVECs. Results demonstrated that AGE-BSAs significantly reduced the cluster of differentiation 31 (CD 31 expression, whereas they promoted the expression of fibroblast-specific protein-1 (FSP-1, α-smooth muscle antibody (α-SMA, and collagen I at both mRNA and protein levels in HUVECs. And the AGE-BSAs also promoted the receptors for AGEs (RAGEs and receptor I for TGF-β (TGFR I markedly with a dose dependence, whereas the Sirt 1 was significantly downregulated by the AGE-BSA at both mRNA and protein levels. Moreover, the Sirt 1 activity manipulation with its activator, resveratrol (RSV, or its inhibitor, EX527, markedly inhibited or ameliorated the AGE-mediated TGF-β upregulation. And the manipulated Sirt 1 activity positively regulated the AGE-induced CD31, whereas it negatively regulated the AGE-induced FSP-1. Thus, Sirt 1 was confirmed to regulate the AGE-induced EndMT via TGF-β. In summary, we found that AGE-BSA induced EndMT in HUVECs via upregulating TGF-β and downregulating Sirt 1, which also negatively regulated TGF-β in the cell. This study implied the EndMT probably as an important mechanism of AGE-induced cardiovascular injury.

  18. Advanced glycation end products induce endothelial-to-mesenchymal transition via downregulating Sirt 1 and upregulating TGF-β in human endothelial cells.

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    He, Wei; Zhang, Jian; Gan, Tian-yi; Xu, Guo-jun; Tang, Bao-peng

    2015-01-01

    In the present study, we examined the advanced glycation end products- (AGEs-) induced endothelial-to-mesenchymal transition (EndMT) in human umbilical vein endothelial cells (HUVECs). Results demonstrated that AGE-BSAs significantly reduced the cluster of differentiation 31 (CD 31) expression, whereas they promoted the expression of fibroblast-specific protein-1 (FSP-1), α-smooth muscle antibody (α-SMA), and collagen I at both mRNA and protein levels in HUVECs. And the AGE-BSAs also promoted the receptors for AGEs (RAGEs) and receptor I for TGF-β (TGFR I) markedly with a dose dependence, whereas the Sirt 1 was significantly downregulated by the AGE-BSA at both mRNA and protein levels. Moreover, the Sirt 1 activity manipulation with its activator, resveratrol (RSV), or its inhibitor, EX527, markedly inhibited or ameliorated the AGE-mediated TGF-β upregulation. And the manipulated Sirt 1 activity positively regulated the AGE-induced CD31, whereas it negatively regulated the AGE-induced FSP-1. Thus, Sirt 1 was confirmed to regulate the AGE-induced EndMT via TGF-β. In summary, we found that AGE-BSA induced EndMT in HUVECs via upregulating TGF-β and downregulating Sirt 1, which also negatively regulated TGF-β in the cell. This study implied the EndMT probably as an important mechanism of AGE-induced cardiovascular injury.

  19. Beneficial Effect of Traditional Chinese Medicinal Formula Danggui-Shaoyao-San on Advanced Glycation End-Product-Mediated Renal Injury in Streptozotocin-Diabetic Rats

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    I-Min Liu

    2012-01-01

    Full Text Available The present study was undertaken to characterize the effects of Danggui-Shaoyao-San (DSS, a famous traditional Chinese medicine formula consisting of six herbal medicines, on diabetic nephropathy. Streptozotocin-induced diabetic rats were orally administrated DSS (2.8 g kg−1 per day for 12 consecutive weeks. DSS partially decreased the high plasma glucose level in diabetic rats. Diabetic-dependent alterations in urinary albumin, 24-hour urinary albumin excretion rate, and creatinine clearance as well as the kidney hypertrophy (kidney weight/body weight ratio and glomerular mesangial matrix expansion were ameliorated after 12 weeks of DSS treatment. The increased expression of nuclear factor-κB as well as transforming growth factor-β1 and the progressive accumulation of type IV collagen in kidney of diabetic rats were also attenuated by DSS. Not only the elevated levels of advanced glycation end products (AGEs and Nε-(carboxymethyllysine but also the higher levels of lipid peroxidation products in kidney of diabetic rats were ameliorated by DSS. Decreased activity of superoxide diamutase and glutathione peroxidase in kidney of diabetic rats was enhanced by DSS. These data demonstrated that the renoprotective effects of DSS in STZ-diabetic rats not only were attributable to regulate plasma glucose to attenuate AGEs expression in diabetic glomeruli but also likely reflected its antioxidant activity.

  20. Far-infrared protects vascular endothelial cells from advanced glycation end products-induced injury via PLZF-mediated autophagy in diabetic mice

    Science.gov (United States)

    Chen, Cheng-Hsien; Chen, Tso-Hsiao; Wu, Mei-Yi; Chou, Tz-Chong; Chen, Jia-Rung; Wei, Meng-Jun; Lee, San-Liang; Hong, Li-Yu; Zheng, Cai-Mei; Chiu, I-Jen; Lin, Yuh-Feng; Hsu, Ching-Min; Hsu, Yung-Ho

    2017-01-01

    The accumulation of advanced glycation end products (AGEs) in diabetic patients induces vascular endothelial injury. Promyelocytic leukemia zinc finger protein (PLZF) is a transcription factor that can be activated by low-temperature far-infrared (FIR) irradiation to exert beneficial effects on the vascular endothelium. In the present study, we investigated the influence of FIR-induced PLZF activation on AGE-induced endothelial injury both in vitro and in vivo. FIR irradiation inhibited AGE-induced apoptosis in human umbilical vein endothelial cells (HUVECs). PLZF activation increased the expression of phosphatidylinositol-3 kinases (PI3K), which are important kinases in the autophagic signaling pathway. FIR-induced PLZF activation led to autophagy in HUVEC, which was mediated through the upregulation of PI3K. Immunofluorescence staining showed that AGEs were engulfed by HUVECs and localized to lysosomes. FIR-induced autophagy promoted AGEs degradation in HUVECs. In nicotinamide/streptozotocin-induced diabetic mice, FIR therapy reduced serum AGEs and AGEs deposition at the vascular endothelium. FIR therapy also reduced diabetes-induced inflammatory markers in the vascular endothelium and improved vascular endothelial function. These protective effects of FIR therapy were not found in PLZF-knockout mice. Our data suggest that FIR-induced PLZF activation in vascular endothelial cells protects the vascular endothelium in diabetic mice from AGE-induced injury. PMID:28071754

  1. Advanced Glycation End Products (AGE) Potently Induce Autophagy through Activation of RAF Protein Kinase and Nuclear Factor κB (NF-κB).

    Science.gov (United States)

    Verma, Neeharika; Manna, Sunil K

    2016-01-15

    Advanced glycation end products (AGE) accumulate in diabetic patients and aging people because of high amounts of three- or four-carbon sugars derived from glucose, thereby causing multiple consequences, including inflammation, apoptosis, obesity, and age-related disorders. It is important to understand the mechanism of AGE-mediated signaling leading to the activation of autophagy (self-eating) that might result in obesity. We detected AGE as one of the potent inducers of autophagy compared with doxorubicin and TNF. AGE-mediated autophagy is inhibited by suppression of PI3K and potentiated by the autophagosome maturation blocker bafilomycin. It increases autophagy in different cell types, and that correlates with the expression of its receptor, receptor for AGE. LC3B, the marker for autophagosomes, is shown to increase upon AGE stimulation. AGE-mediated autophagy is partially suppressed by inhibitor of NF-κB, PKC, or ERK alone and significantly in combination. AGE increases sterol regulatory element binding protein activity, which leads to an increase in lipogenesis. Although AGE-mediated lipogenesis is affected by autophagy inhibitors, AGE-mediated autophagy is not influenced by lipogenesis inhibitors, suggesting that the turnover of lipid droplets overcomes the autophagic clearance. For the first time, we provide data showing that AGE induces several cell signaling cascades, like NF-κB, PKC, ERK, and MAPK, that are involved in autophagy and simultaneously help with the accumulation of lipid droplets that are not cleared effectively by autophagy, therefore causing obesity.

  2. Voltammetric Detection of S100B Protein Using His-Tagged Receptor Domains for Advanced Glycation End Products (RAGE Immobilized onto a Gold Electrode Surface

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    Edyta Mikuła

    2014-06-01

    Full Text Available In this work we report on an electrochemical biosensor for the determination of the S100B protein. The His-tagged VC1 domains of Receptors for Advanced Glycation End (RAGE products used as analytically active molecules were covalently immobilized on a monolayer of a thiol derivative of pentetic acid (DPTA complex with Cu(II deposited on a gold electrode surface. The recognition processes between the RAGE VC1 domain and the S100B protein results in changes in the redox activity of the DPTA-Cu(II centres which were measured by Osteryoung square-wave voltammetry (OSWV. In order to verify whether the observed analytical signal originates from the recognition process between the His6–RAGE VC1 domains and the S100B protein, the electrode modified with the His6–RAGE C2 and His6–RAGE VC1 deleted domains which have no ability to bind S100B peptides were applied. The proposed biosensor was quite sensitive, with a detection limit of 0.52 pM recorded in the buffer solution. The presence of diluted human plasma and 10 nM Aβ1-40 have no influence on the biosensor performance.

  3. Soluble Receptor for Advanced Glycation End Product Ameliorates Chronic Intermittent Hypoxia Induced Renal Injury, Inflammation, and Apoptosis via P38/JNK Signaling Pathways

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    Xu Wu

    2016-01-01

    Full Text Available Obstructive sleep apnea (OSA associated chronic kidney disease is mainly caused by chronic intermittent hypoxia (CIH triggered tissue damage. Receptor for advanced glycation end product (RAGE and its ligand high mobility group box 1 (HMGB1 are expressed on renal cells and mediate inflammatory responses in OSA-related diseases. To determine their roles in CIH-induced renal injury, soluble RAGE (sRAGE, the RAGE neutralizing antibody, was intravenously administered in a CIH model. We also evaluated the effect of sRAGE on inflammation and apoptosis. Rats were divided into four groups: (1 normal air (NA, (2 CIH, (3 CIH+sRAGE, and (4 NA+sRAGE. Our results showed that CIH accelerated renal histological injury and upregulated RAGE-HMGB1 levels involving inflammatory (NF-κB, TNF-α, and IL-6, apoptotic (Bcl-2/Bax, and mitogen-activated protein kinases (phosphorylation of P38, ERK, and JNK signal transduction pathways, which were abolished by sRAGE but p-ERK. Furthermore, sRAGE ameliorated renal dysfunction by attenuating tubular endothelial apoptosis determined by immunofluorescence staining of CD31 and TUNEL. These findings suggested that RAGE-HMGB1 activated chronic inflammatory transduction cascades that contributed to the pathogenesis of the CIH-induced renal injury. Inhibition of RAGE ligand interaction by sRAGE provided a therapeutic potential for CIH-induced renal injury, inflammation, and apoptosis through P38 and JNK pathways.

  4. Early expression of the receptor for advanced glycation end products in a toxic model produced by 6-hydroxydopamine in the rat striatum.

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    Serratos, Iris N; Castellanos, Pilar; Pastor, Nina; Millán-Pacheco, César; Colín-González, Ana Laura; Rembao, Daniel; Pérez-Montfort, Ruy; Cabrera, Nallely; Sánchez-García, Aurora; Gómez, Isabel; Rangel-López, Edgar; Santamaria, Abel

    2016-04-05

    The receptor for advanced glycation end products (RAGE) is commonly involved in different neurodegenerative and inflammatory disorders. The cellular signaling associated to RAGE activation may occur upon binding to different ligands. In this study we investigated whether the toxic model produced by 6-hydroxydopamine (6-OHDA) in rats comprises early noxious responses related to RAGE-mediated signaling cascades. In order to explore a possible interaction between 6-OHDA and RAGE, affinity parameters of RAGE with 6-OHDA were estimated by different means. The possible binding sites of 6-OHDA with the VC1 homodimer for both rat and human RAGE were also modeled. Our results show that the striatal infusion of 6-OHDA recruits RAGE upregulation, as evidenced by an early expression of the receptor. 6-OHDA was also found to bind the VC1 homodimer, although its affinity was moderate when compared to other ligands. This work contributes to the understanding of the role of RAGE activation for 6-OHDA-induced neurotoxicity.

  5. Opposing roles of membrane and soluble forms of the receptor for advanced glycation end products in primary respiratory syncytial virus infection.

    Science.gov (United States)

    Miller, Allison L; Sims, Gary P; Brewah, Yambasu A; Rebelatto, Marlon C; Kearley, Jennifer; Benjamin, Ebony; Keller, Ashley E; Brohawn, Philip; Herbst, Ronald; Coyle, Anthony J; Humbles, Alison A; Kolbeck, Roland

    2012-04-15

    Respiratory syncytial virus (RSV), a common respiratory pathogen in infants and the older population, causes pulmonary inflammation and airway occlusion that leads to impairment of lung function. Here, we have established a role for receptor for advanced glycation end products (RAGE) in RSV infection. RAGE-deficient (ager(-/-)) mice were protected from RSV-induced weight loss and inflammation. This protection correlated with an early increase in type I interferons, later decreases in proinflammatory cytokines, and a reduction in viral load. To assess the contribution of soluble RAGE (sRAGE) to RSV-induced disease, wild-type and ager(-/-) mice were given doses of sRAGE following RSV infection. Of interest, sRAGE treatment prevented RSV-induced weight loss and neutrophilic inflammation to a degree similar to that observed in ager(-/-) mice. Our work further elucidates the roles of RAGE in the pathogenesis of respiratory infections and highlights the opposing roles of membrane and sRAGE in modulating the host response to RSV infection.

  6. DNA aptamer raised against advanced glycation end products (AGEs) improves glycemic control and decreases adipocyte size in fructose-fed rats by suppressing AGE-RAGE axis.

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    Ojima, A; Matsui, T; Nakamura, N; Higashimoto, Y; Ueda, S; Fukami, K; Okuda, S; Yamagishi, S

    2015-04-01

    Advanced glycation end products (AGEs) decrease adiponectin expression and suppress insulin signaling in cultured adipocytes through the interaction with a receptor for AGEs (RAGE) via oxidative stress generation. We have recently found that high-affinity DNA aptamer directed against AGE (AGE-aptamer) prevents the progression of experimental diabetic nephropathy by blocking the harmful actions of AGEs in the kidney. This study examined the effects of AGE-aptamer on adipocyte remodeling, AGE-RAGE-oxidative stress axis, and adiponectin expression in fructose-fed rats. Although AGE-aptamer treatment by an osmotic mini pump for 8 weeks did not affect serum insulin levels, it significantly decreased average fasting blood glucose and had a tendency to inhibit body weight gain in fructose-fed rats. Furthermore, AGE-aptamer significantly suppressed the increase in adipocyte size and prevented the elevation in AGEs, RAGE, and an oxidative stress marker, 8-hydroxydeoxyguanosine (8-OHdG), levels in adipose tissues of fructose-fed rats at 14-week-old, while it restored the decrease in adiponectin mRNA levels. Our present study suggests that AGE-aptamer could improve glycemic control and prevent adipocyte remodeling in fructose-fed rats partly by suppressing the AGE-RAGE-mediated oxidative stress generation. AGE-aptamer might be a novel therapeutic strategy for fructose-induced metabolic derangements.

  7. Positive association of circulating levels of advanced glycation end products (AGEs) with pigment epithelium-derived factor (PEDF) in a general population.

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    Yamagishi, Sho-Ichi; Matsui, Takanori; Adachi, Hisashi; Takeuchi, Masayoshi

    2010-02-01

    We have recently found that serum levels of pigment epithelium-derived factor (PEDF), a glycoprotein with anti-oxidative and anti-inflammatory properties, are elevated in proportion to the accumulation of the number of the components of the metabolic syndrome. Since formation and accumulation of advanced glycation end products (AGEs) progress under the metabolic syndrome and that PEDF could inhibit the AGE-elicited tissue damage, it is conceivable that PEDF levels may be increased as a counter-system against AGEs in patients with the metabolic syndrome. However, correlation between circulating levels of AGEs and PEDF in humans remains to be elucidated. In this study, we investigated the relationship between serum AGE and PEDF levels in a general population and examined the effects of AGEs on PEDF gene expression in vitro. One hundred ninety-six Japanese subjects in a general population underwent a complete history and physical examination, determination of blood chemistries, including serum levels of AGEs and PEDF. In multiple regression analyses, creatinine, body mass index, triglycerides, AGEs and insulin were independently correlated with serum PEDF levels. AGEs dose-dependently increased PEDF gene expression in cultured adipocytes and liver cells. Our present study demonstrated first that circulating AGEs were one of the independent correlates of serum levels of PEDF. Adipose tissue and liver may be target organs for the AGE-induced PEDF overexpression in humans. Serum PEDF levels may be elevated in response to circulating AGEs as a counter-system against the AGE-elicited tissue damage.

  8. Suppression of antioxidant Nrf-2 and downstream pathway in H9c2 cells by advanced glycation end products (AGEs) via ERK phosphorylation.

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    Ko, Shun-Yao; Chang, Shu-Shing; Lin, I-Hsuan; Chen, Hong-I

    2015-11-01

    Diabetic cardiomyopathy is related to oxidative stress and correlated with the presence of advanced glycation end products (AGEs). In a clinical setting, AGEs can be detected in patients presenting diabetic cardiomyopathy; however, the underlying mechanism has yet to be elucidated. In our previous study, AGEs increase cell hypertrophy via ERK phosphorylation in a process closely related to ROS production. Thus, we propose that AGEs regulate the antioxidant gene nuclear factor-erythroid 2-related factor (Nrf-2). In H9c2 cells treated with AGEs, the expression of Nrf-2 was reduced; however, ERK phosphorylation was shown to increase. Treatment with H2O2 was also shown to increase Nrf-2 and ERK phosphorylation. In cells pretreatment with ROS scavenger NAC, the effects of H2O2 were reduced; however, the effects of the AGEs remained largely unchanged. Conversely, when cells were pretreated with PD98059 (ERK inhibitor), the expression of Nrf-2 was recovered following treatment with AGEs. Our results suggest that AGEs inhibit Nrf-2 via the ERK pathway; however, this influence is partly associated with ROS. Our finding further indicated that AGEs possess both ROS-dependent and ROS-independent pathways, resulting in a reduction in Nrf-2. This report reveals an important mechanism underlying the regulation of diabetic cardiomyopathy progression by AGEs.

  9. Inhibition of protein glycation by procyanidin-B2 enriched fraction of cinnamon: delay of diabetic cataract in rats.

    Science.gov (United States)

    Muthenna, Puppala; Raghu, Ganugula; Akileshwari, Chandrasekhar; Sinha, Sukesh Narayana; Suryanarayana, Palla; Reddy, Geereddy Bhanuprakash

    2013-11-01

    Accumulation of advanced glycation endproducts (AGE) from nonenzymatic glycation of proteins has been implicated in several diabetic complications including diabetic cataract. Previously, we have reported that extracts of dietary agents such as cinnamon have the potential to inhibit AGE formation. In this study, we have shown procyanidin-B2 as the active component of cinnamon that is involved in AGE inhibition using bioassay-guided fractionation of eye lens proteins under in vitro conditions. The data indicate that procyanidin-B2 enriched fraction scavenges dicarbonyls. Further, procyanidin-B2 fraction of cinnamon inhibited the formation of glycosylated hemoglobin in human blood under ex vivo conditions. We have also demonstrated the physiological significance of procyanidin-B2 fraction in terms of delay of diabetic cataract through inhibition of AGE in diabetic rats. These findings establish the antiglycating potential of procyanidin-B2 fraction of cinnamon which suggests a scope for controlling AGE-mediated diabetic complications by food sources that are rich in proanthocyanidins like procyanidin-B2.

  10. The effects of Advanced Glycation End Products (RAGE)-374T/A and Gly82Ser variants and soluble-RAGE levels to obesity in children.

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    Kucukhuseyin, O; Ozgen, T; Karagedik, E H; Cesur, Y; Yilmaz Aydogan, H; Yaylim, I; Ergen, H A

    2016-04-30

    In recent years, studies related to advanced glycation end products (AGE) and their interaction with their receptors (RAGE) have advanced our knowledge of the roles of these molecules in different diseases. However, studies concerning AGE-RAGE interaction in obesity are limited and the results are conflicting. RAGE gene is located on 6p21.3, has several polymorphic sites including -374T/A, a functional polymorphism in the promoter region, and Gly82Ser, present within the ligand-binding domain. In the present study, the determination of possible risks in the development of obesity according to RAGE polymorhisms and plasma levels of RAGE (sRAGE) was aimed. 87 obese and 78 healthy children were included in this study. Genomic DNA was isolated with salting-out procedure. RAGE polymorphisms were analyzed by PCR based techniques. In contrast to Gly82Ser, -374T/A allelic and genotypic frequencies were not different between study groups. Ser(SerSer+GlySer genotype) allele frequency was higher in obese cases than controls (74.20%→25.80%,OR:2.573,95%CI:1.789-3.699;pGlySer>GlyGly for HDL-C, and opposite for FT4. Besides, Ser carriers had lower insulin (p=0.038) and homa-IR (p=0.081) levels than GG genotype. sRAGE levels were different between obese and control seperately or in combination with RAGE polymorphisms (pTA>AA for -374T/A and SerSer>GlyGly>GlySer for Gly82Ser. According to our results SerSer genotype could have significant effects on sRAGE levels, and increased sRAGE levels and Gly82Ser polymorphism either combinatorially or seperately increased the propensity towards obesity.

  11. DNA Advanced Glycation End Products (DNA-AGEs) Are Elevated in Urine and Tissue in an Animal Model of Type 2 Diabetes.

    Science.gov (United States)

    Jaramillo, Richard; Shuck, Sarah C; Chan, Yin S; Liu, Xueli; Bates, Steven E; Lim, Punnajit P; Tamae, Daniel; Lacoste, Sandrine; O'Connor, Timothy R; Termini, John

    2017-02-20

    More precise identification and treatment monitoring of prediabetic/diabetic individuals will require additional biomarkers to complement existing diagnostic tests. Candidates include hyperglycemia-induced adducts such as advanced glycation end products (AGEs) of proteins, lipids, and DNA. The potential for DNA-AGEs as diabetic biomarkers was examined in a longitudinal study using the Lepr(db/db) animal model of metabolic syndrome. The DNA-AGE, N(2)-(1-carboxyethyl)-2'-deoxyguanosine (CEdG) was quantified by mass spectrometry using isotope dilution from the urine and tissue of hyperglycemic and normoglycemic mice. Hyperglycemic mice (fasting plasma glucose, FPG, ≥ 200 mg/dL) displayed a higher median urinary CEdG value (238.4 ± 112.8 pmol/24 h) than normoglycemic mice (16.1 ± 11.8 pmol/24 h). Logistic regression analysis revealed urinary CEdG to be an independent predictor of hyperglycemia. Urinary CEdG was positively correlated with FPG in hyperglycemic animals and with HbA1c for all mice. Average tissue-derived CEdG was also higher in hyperglycemic mice (18.4 CEdG/10(6) dG) than normoglycemic mice (4.4 CEdG/10(6) dG). Urinary CEdG was significantly elevated in Lepr(db/db) mice relative to Lepr(wt/wt), and tissue CEdG values increased in the order Lepr(wt/wt) < Lepr(wt/db) < Lepr(db/db). These data suggest that urinary CEdG measurement may provide a noninvasive quantitative index of glycemic status and augment existing biomarkers for the diagnosis and monitoring of diabetes.

  12. Fibroblast growth factor 21 protects mouse brain against D-galactose induced aging via suppression of oxidative stress response and advanced glycation end products formation.

    Science.gov (United States)

    Yu, Yinhang; Bai, Fuliang; Wang, Wenfei; Liu, Yaonan; Yuan, Qingyan; Qu, Susu; Zhang, Tong; Tian, Guiyou; Li, Siming; Li, Deshan; Ren, Guiping

    2015-06-01

    Fibroblast growth factor 21 (FGF21) is a hormone secreted predominantly in the liver, pancreas and adipose tissue. Recently, it has been reported that FGF21-Transgenic mice can extend their lifespan compared with wild type counterparts. Thus, we hypothesize that FGF21 may play some roles in aging of organisms. In this study d-galactose (d-gal)-induced aging mice were used to study the mechanism that FGF21 protects mice from aging. The three-month-old Kunming mice were subcutaneously injected with d-gal (180mg·kg(-1)·d(-1)) for 8weeks and administered simultaneously with FGF21 (1, 2 or 5mg·kg(-1)·d(-1)). Our results showed that administration of FGF21 significantly improved behavioral performance of d-gal-treated mice in water maze task and step-down test, reduced brain cell damage in the hippocampus, and attenuated the d-gal-induced production of MDA, ROS and advanced glycation end products (AGEs). At the same time, FGF21 also markedly renewed the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and total anti-oxidation capability (T-AOC), and decreased the enhanced total cholinesterase (TChE) activity in the brain of d-gal-treated mice. The expression of aldose reductase (AR), sorbitol dehydrogenase (SDH) and member-anchored receptor for AGEs (RAGE) declined significantly after FGF21 treatment. Furthermore, FGF21 suppressed inflamm-aging by inhibiting IκBα degradation and NF-κB p65 nuclear translocation. The expression levels of pro-inflammatory cytokines, such as TNF-α and IL-6, decreased significantly. In conclusion, these results suggest that FGF21 protects the aging mice brain from d-gal-induced injury by attenuating oxidative stress damage and decreasing AGE formation.

  13. High-mobility group box 1 inhibits gastric ulcer healing through Toll-like receptor 4 and receptor for advanced glycation end products.

    Science.gov (United States)

    Nadatani, Yuji; Watanabe, Toshio; Tanigawa, Tetsuya; Ohkawa, Fumikazu; Takeda, Shogo; Higashimori, Akira; Sogawa, Mitsue; Yamagami, Hirokazu; Shiba, Masatsugu; Watanabe, Kenji; Tominaga, Kazunari; Fujiwara, Yasuhiro; Takeuchi, Koji; Arakawa, Tetsuo

    2013-01-01

    High-mobility group box 1 (HMGB1) was initially discovered as a nuclear protein that interacts with DNA as a chromatin-associated non-histone protein to stabilize nucleosomes and to regulate the transcription of many genes in the nucleus. Once leaked or actively secreted into the extracellular environment, HMGB1 activates inflammatory pathways by stimulating multiple receptors, including Toll-like receptor (TLR) 2, TLR4, and receptor for advanced glycation end products (RAGE), leading to tissue injury. Although HMGB1's ability to induce inflammation has been well documented, no studies have examined the role of HMGB1 in wound healing in the gastrointestinal field. The aim of this study was to evaluate the role of HMGB1 and its receptors in the healing of gastric ulcers. We also investigated which receptor among TLR2, TLR4, or RAGE mediates HMGB1's effects on ulcer healing. Gastric ulcers were induced by serosal application of acetic acid in mice, and gastric tissues were processed for further evaluation. The induction of ulcer increased the immunohistochemical staining of cytoplasmic HMGB1 and elevated serum HMGB1 levels. Ulcer size, myeloperoxidase (MPO) activity, and the expression of tumor necrosis factor α (TNFα) mRNA peaked on day 4. Intraperitoneal administration of HMGB1 delayed ulcer healing and elevated MPO activity and TNFα expression. In contrast, administration of anti-HMGB1 antibody promoted ulcer healing and reduced MPO activity and TNFα expression. TLR4 and RAGE deficiency enhanced ulcer healing and reduced the level of TNFα, whereas ulcer healing in TLR2 knockout (KO) mice was similar to that in wild-type mice. In TLR4 KO and RAGE KO mice, exogenous HMGB1 did not affect ulcer healing and TNFα expression. Thus, we showed that HMGB1 is a complicating factor in the gastric ulcer healing process, which acts through TLR4 and RAGE to induce excessive inflammatory responses.

  14. High-mobility group box 1 inhibits gastric ulcer healing through Toll-like receptor 4 and receptor for advanced glycation end products.

    Directory of Open Access Journals (Sweden)

    Yuji Nadatani

    Full Text Available High-mobility group box 1 (HMGB1 was initially discovered as a nuclear protein that interacts with DNA as a chromatin-associated non-histone protein to stabilize nucleosomes and to regulate the transcription of many genes in the nucleus. Once leaked or actively secreted into the extracellular environment, HMGB1 activates inflammatory pathways by stimulating multiple receptors, including Toll-like receptor (TLR 2, TLR4, and receptor for advanced glycation end products (RAGE, leading to tissue injury. Although HMGB1's ability to induce inflammation has been well documented, no studies have examined the role of HMGB1 in wound healing in the gastrointestinal field. The aim of this study was to evaluate the role of HMGB1 and its receptors in the healing of gastric ulcers. We also investigated which receptor among TLR2, TLR4, or RAGE mediates HMGB1's effects on ulcer healing. Gastric ulcers were induced by serosal application of acetic acid in mice, and gastric tissues were processed for further evaluation. The induction of ulcer increased the immunohistochemical staining of cytoplasmic HMGB1 and elevated serum HMGB1 levels. Ulcer size, myeloperoxidase (MPO activity, and the expression of tumor necrosis factor α (TNFα mRNA peaked on day 4. Intraperitoneal administration of HMGB1 delayed ulcer healing and elevated MPO activity and TNFα expression. In contrast, administration of anti-HMGB1 antibody promoted ulcer healing and reduced MPO activity and TNFα expression. TLR4 and RAGE deficiency enhanced ulcer healing and reduced the level of TNFα, whereas ulcer healing in TLR2 knockout (KO mice was similar to that in wild-type mice. In TLR4 KO and RAGE KO mice, exogenous HMGB1 did not affect ulcer healing and TNFα expression. Thus, we showed that HMGB1 is a complicating factor in the gastric ulcer healing process, which acts through TLR4 and RAGE to induce excessive inflammatory responses.

  15. Nifedipine inhibits advanced glycation end products (AGEs) and their receptor (RAGE) interaction-mediated proximal tubular cell injury via peroxisome proliferator-activated receptor-gamma activation

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Takanori [Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, Kurume (Japan); Yamagishi, Sho-ichi, E-mail: shoichi@med.kurume-u.ac.jp [Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, Kurume (Japan); Takeuchi, Masayoshi [Department of Pathophysiological Science, Faculty of Pharmaceutical Science, Hokuriku University, Kanazawa (Japan); Ueda, Seiji; Fukami, Kei; Okuda, Seiya [Department of Medicine, Kurume University School of Medicine, Kurume (Japan)

    2010-07-23

    Research highlights: {yields} Nifedipine inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma}. {yields} GW9662 treatment alone increased RAGE mRNA levels in tubular cells. {yields} Nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-{kappa}B activation and increases in intercellular adhesion molecule-1 and transforming growth factor-{beta} gene expression in tubular cells, all of which were blocked by GW9662. -- Abstract: There is a growing body of evidence that advanced glycation end products (AGEs) and their receptor (RAGE) interaction evokes oxidative stress generation and subsequently elicits inflammatory and fibrogenic reactions, thereby contributing to the development and progression of diabetic nephropathy. We have previously found that nifedipine, a calcium-channel blocker (CCB), inhibits the AGE-induced mesangial cell damage in vitro. However, effects of nifedipine on proximal tubular cell injury remain unknown. We examined here whether and how nifedipine blocked the AGE-induced tubular cell damage. Nifedipine, but not amlodipine, a control CCB, inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}). GW9662 treatment alone was found to increase RAGE mRNA levels in tubular cells. Further, nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-{kappa}B activation and increases in intercellular adhesion molecule-1 and transforming growth factor-beta gene expression in tubular cells, all of which were blocked by GW9662. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-oxidative and anti-inflammatory agent against AGEs in tubular cells by suppressing RAGE expression

  16. Associations between Soluble Receptor for Advanced Glycation End Products (sRAGE) and S100A12 (EN-RAGE) with Mortality in Long-term Hemodialysis Patients.

    Science.gov (United States)

    Jung, Eul Sik; Chung, Wookyung; Kim, Ae Jin; Ro, Han; Chang, Jae Hyun; Lee, Hyun Hee; Jung, Ji Yong

    2017-01-01

    Hemodialysis (HD) patients experience vascular calcification, ultimately leading to high mortality rates. Previously, we reported associations between soluble receptor for advanced glycation end products (sRAGEs) and extracellular newly identified RAGE-binding protein S100A12 (EN-RAGE) and vascular calcification. Here, we extended our observations, investigating whether these biomarkers may be useful for predicting cardiovascular morbidity and mortality in these subjects. Thus, we evaluated the relationship between sRAGE and S100A12 and mortality in long-term HD patients. This was a prospective observational cohort study in 199 HD patients from an extended analysis of our previous study. Plasma sRAGE, S100A12, comorbidities, and other traditional risk factors were investigated. The cumulative incidences for death using Cox proportional hazards regression were evaluated in multivariable analyses. The observation period was 44 months. During the observation period, 27 (13.6%) patients died. Univariate analysis demonstrated that S100A12 was correlated with diabetes (P = 0.040) and high-sensitivity C-reactive protein (hsCRP) (P = 0.006). In multivariable analyses, plasma sRAGE (hazard ratio [HR] = 1.155; 95% confidence interval [CI] = 0.612-2.183; P = 0.656) and S100A12 (HR = 0.960; 95% CI = 0.566-1.630; P = 0.881) were not associated with mortality in HD patients, although traditional predictors of mortality, including age, history of cardiovascular diseases (CVDs), and serum levels of albumin and hsCRP were related to mortality. Powerful predictors of mortality were age, CVD, and albumin levels. Plasma sRAGE and S100A12 may be weak surrogate markers for predicting all-cause mortality in patients undergoing HD, although S100A12 was partly related to diabetes and inflammation.

  17. Metformin inhibits advanced glycation end products (AGEs)-induced renal tubular cell injury by suppressing reactive oxygen species generation via reducing receptor for AGEs (RAGE) expression.

    Science.gov (United States)

    Ishibashi, Y; Matsui, T; Takeuchi, M; Yamagishi, S

    2012-11-01

    Advanced glycation end products (AGEs) and their receptor (RAGE) play a role in tubulointerstitial damage in diabetic nephropathy. Recently, metformin has been shown to ameliorate tubular injury both in cell culture and diabetic animal model. However, effects of metformin on AGEs-induced tubular cell apoptosis and damage remain unknown. We examined here whether and how metformin could block the AGEs-RAGE-elicited tubular cell injury in vitro. Gene expression level was evaluated by real-time reverse-transcription polymerase chain reactions. Reactive oxygen species (ROS) generation was measured with dihydroethidium staining. Apoptosis was evaluated by DNA fragmentation and annexin V expression level. AGEs upregulated RAGE mRNA levels and subsequently increased ROS generation and intercellular adhesion molecule-1, monocyte chemoattractant protein-1 and transforming growth factor-β gene expression in human renal proximal tubular cells, all of which were significantly blocked by the treatment of 0.01 and 0.1 mM metformin. Compound C, an inhibitor of AMP-activated protein kinase significantly blocked the effects of metformin on RAGE gene expression and ROS generation in AGEs-exposed tubular cells. Furthermore, metformin dose-dependently inhibited the AGEs-induced apoptotic cell death of tubular cells; 1 mM metformin completely suppressed the pro-apoptotic effects of AGEs in 2 different assay systems. Our present study suggests that metformin could inhibit the AGEs-induced apoptosis and inflammatory and fibrotic reactions in tubular cells probably by reducing ROS generation via suppression of RAGE expression through AMP-activated protein kinase activation. Metformin may protect against tubular cell injury in diabetic nephropathy by blocking the AGEs-RAGE-ROS axis.

  18. Pravastatin inhibits advanced glycation end products (AGEs)-induced proximal tubular cell apoptosis and injury by reducing receptor for AGEs (RAGE) level.

    Science.gov (United States)

    Ishibashi, Yuji; Yamagishi, Sho-ichi; Matsui, Takanori; Ohta, Keisuke; Tanoue, Ryuichiro; Takeuchi, Masayoshi; Ueda, Seiji; Nakamura, Kei-ichiro; Okuda, Seiya

    2012-08-01

    Advanced glycation end products (AGEs) and their receptor (RAGE) axis play a role in diabetic nephropathy. Statins have been shown to ameliorate renal function and reduce proteinuria in patients with chronic kidney disease. However, the effects of statin on AGEs-induced tubular cell damage remain unknown. We examined here whether and how pravastatin could block the AGEs-RAGE-elicited tubular cell injury in vitro. Gene expression level was evaluated by real-time reverse-transcription polymerase chain reactions. Reactive oxygen species (ROS) generation was measured with dihydroethidium staining. Apoptosis was analyzed in an enzyme-linked immunosorbent assay. Asymmetric dimethylarginine (ADMA) expression was evaluated by immunostaining. Pravastatin dose-dependently inhibited the AGEs-induced up-regulation of RAGE mRNA level, ROS generation and apoptosis in human renal proximal tubular cells. Further, AGEs decreased mRNA level of dimethylarginine dimethylaminohydrolase-2, an enzyme that mainly degrades asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase and subsequently increased ADMA generation in tubular cells, both of which were also prevented by pravastatin. Geranylgeranyl pyrophosphate (GGPP) treatment blocked all of the effects of pravastatin on tubular cells. We found that rosuvastatin also significantly blocked the AGEs-induced increase in RAGE mRNA level and ROS generation, both of which were prevented by GGPP. Our present study suggests that pravastatin could inhibit the AGEs-induced apoptosis and ADMA generation in tubular cells by suppressing RAGE expression probably via inhibition of GGPP synthesis. Pravastatin may exert beneficial effects on tubular damage in diabetic nephropathy by blocking the AGEs-RAGE axis.

  19. Interaction of the S100A6 mutant (C3S) with the V domain of the receptor for advanced glycation end products (RAGE)

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Sepuru K., E-mail: mohansepuri@gmail.com; Gupta, Arun A., E-mail: ninja14gupta@gmail.com; Yu, Chin, E-mail: cyu.nthu@gmail.com

    2013-05-03

    Highlights: •The halo human S100A6 (C3S) NMR chemical shifts were assigned. •The interactions between S100A6m and RAGE V domain was investigated by ITC. •The residues involved in the S100A6m–RAGE V domain binding were mapped by {sup 1}H–{sup 15}N HSQC titration. •S100A6–RAGE V domain tetrameric complex model was generated from NMR studies. •The S100A6–RAGE V domain interface regions were elucidated based on HADDOCK model. -- Abstract: S100A6 is involved in several vital biological functions, such as calcium sensing and cell proliferation. It is a homodimeric protein that belongs to the S100 protein family. The receptor for advanced glycation end products (RAGE) has been shown to play a role in the progression of various disease conditions, such as diabetes and immune/inflammatory disorders. Information regarding the association of RAGE with S100 proteins at a molecular level is useful to understand the diversity of the RAGE signaling pathways. In this report, biomolecular NMR techniques were utilized for the resonance assignment of the C3S mutation in human S100A6 and characterizing its interaction with the RAGE V domain. Further binding affinity between S100A6m and the RAGE V domain was determined by isothermal titration calorimetric studies. HADDOCK was used to generate a heterotetramer model of the S100A6m–RAGE V domain complex. This model provides an important insights into the S100–RAGE cellular signaling pathway.

  20. Glycative Stress and Its Defense Machinery Glyoxalase 1 in Renal Pathogenesis

    Science.gov (United States)

    Hirakawa, Yosuke; Inagi, Reiko

    2017-01-01

    Chronic kidney disease is a major public health problem around the world. Because the kidney plays a role in reducing glycative stress, renal dysfunction results in increased glycative stress. In turn, glycative stress, especially that due to advanced glycated end products (AGEs) and their precursors such as reactive carbonyl compounds, exacerbates chronic kidney disease and is related to premature aging in chronic kidney disease, whether caused by diabetes mellitus or otherwise. Factors which hinder a sufficient reduction in glycative stress include the inhibition of anti-glycation enzymes (e.g., GLO-1), as well as pathogenically activated endoplasmic reticulum (ER) stress and hypoxia in the kidney. Promising strategies aimed at halting the vicious cycle between chronic kidney disease and increases in glycative stress include the suppression of AGE accumulation in the body and the enhancement of GLO-1 to strengthen the host defense machinery against glycative stress. PMID:28106734

  1. Correlation between Advanced Glycation End Products and Vascular Function in Patients with Metabolic Syndrome%代谢综合征患者晚期糖基化终产物与血管内皮功能的相关性

    Institute of Scientific and Technical Information of China (English)

    刘世明; 王丽; 李国强; 晋荣; 成传访; 田朝伟; 钟赟; 陈敏生

    2012-01-01

    Objective To investigate the correlation between advanced glycation end products ( AGEs) and flow -mediated vasodilatation (FMD) in patients with metabolic syndrome (MS). Methods One hundred and eighty patients were randomly selected for epidemiologie follow - up study, including 60 cases without MS ( non metabolic syndrome, NMS) , 60 cases with MS but without diabetes mellitus (metabolic syndrome without diabetes mellitus, NDMMS) , 60 cases with MS with DM (metabolic syndrome with diabetes mellitus,DMMS). FMD and nitroglycerin - induced vasodilatation (NMD) were determined by the philips IE33 ultrasonic machine, and plasma AGEs were measured by ELISA. Results AGEs levels were significantly higher in NDMMS and DMMS patients compared with NMS patients (P < 0. 05 ) , and AGEs levels in DMMS patients were higher than those in NDMMS patients (P < 0. 05) ; FMD in DMMS patients was significantly lower than that in NDMMS and NMS patients(P <0. 05) ; NMD was lower in NDMMS DMMS patients compared with NMS patients(P<0. 05) , and NMD in DMMS patients was lower than that in NDMMS patients (P < 0. 05 ) ; AGEs was significantly negatively correlated with FMD and NMD(r= -0.23, P <0. 05; r= -0.19, P<0. 05). Multiple linear regression analysis showed AGEs and age were the risk factors for impaired FMD. Conclusion AGEs may be one of the risk factors for causing vascular endothelial dysfunction in patients with metabolic syndrome.%目的 探讨代谢综合征(metabolic syndrome)患者血浆中晚期糖基化终产物(advanced glycation endproducts,AGEs)与血流介导内皮依赖性血管舒张功能(flow-mediated vasodilatation,FMD)的关系.方法 采用流行病学方法随机抽取180例随访者作为研究对象,其中非代谢综合征(NMS)患者60例(NMS组),非糖尿病代谢综合征(NDMMS)患者60例(NDMMS组),糖尿病代谢综合征(DMMS)患者60例(DMMS组),采用飞利浦IE33超声杌测定FMD及硝酸甘油介导血管肉皮功能(nitroglycerin-induced vasodilatation

  2. Advanced glycation end products promote human aortic smooth muscle cell calcification in vitro via activating NF-κB and down-regulating IGF1R expression

    Institute of Scientific and Technical Information of China (English)

    Yi WANG; Zhen-yu ZHANG; Xiao-qing CHEN; Xiang WANG; Heng CAO; Shao-wen LIU

    2013-01-01

    Aim:To investigate the effects of advanced glycation end products (AGEs) on calcification in human aortic smooth muscle cells (HASMCs) in vitro and the underlying mechanisms.Methods:AGEs were artificially prepared.Calcification of HASMCs was induced by adding inorganic phosphate (Pi,2 mmol/L) in the media,and observed with Alizarin red staining.The calcium content in the supernatant was measured using QuantiChrome Calcium Assay Kit.Expression of the related mRNAs and proteins was analyzed using real-time PCR and Western blot,respectively.Chromatin immunoprecipitation (ChIP) assay was used to detect the binding of NF-κB to the putative IGF1R promoter.Results:AGEs (100 μg/mL) significantly enhanced Pi-induced calcification and the levels of osteocalcin and Cbfα1 in HASMCs.Furthermore,the treatment decreased the expression of insulin-like growth factor 1 receptor (IGF1R).Over-expression of IGF1R in HASMCs suppressed the AGEs-induced increase in calcium deposition.When IGF1R expression was knocked down in HASMCs,AGEs did not enhance the calcium deposition.Meanwhile,AGEs time-dependently decreased the amounts of IκBα and Flag-tagged p65 in the cytoplasmic extracts,and increased the amount of nuclear p65 in HASMCs.In the presence of NF-κB inhibitor PDTC (50 μmol/L),the AGEs-induced increase in calcium deposition was blocked.Over-expression of p65 significantly enhanced Pi-induced mineralization,but suppressed IGF1R mRNA level.Knockdown of p65 suppressed the AGEs-induced increase in calcium deposition,and rescued the IGF1R expression.The ChIP analysis revealed that NF-κB bound the putative IGF1R promoter at position-230 to-219 bp.The inhibition of IGF1R by NF-κB was abolished when IGF1R reporter plasmid contained mutated binding sequence for NF-κB or an NF-κB reporter vector.Conclusion:The results demonstrate that AGEs promote calcification of human aortic smooth muscle cells in vitro via activation of NF-κB and down-regulation of IGF1R expression.

  3. HMGB1 Contributes to the Expression of P-Glycoprotein in Mouse Epileptic Brain through Toll-Like Receptor 4 and Receptor for Advanced Glycation End Products.

    Directory of Open Access Journals (Sweden)

    Yan Chen

    Full Text Available The objective of the present study was to investigate the role of high-mobility group box-1 (HMGB1 in the seizure-induced P-glycoprotein (P-gp overexpression and the underlying mechanism. Kainic acid (KA-induced mouse seizure model was used for in vivo experiments. Male C57BL/6 mice were divided into four groups: normal saline control (NS group, KA-induced epileptic seizure (EP group, and EP group pretreated with HMGB1 (EP+HMGB1 group or BoxA (HMGB1 antagonist, EP+BoxA group. Compared to the NS group, increased levels of HMGB1 and P-gp in the brain were observed in the EP group. Injection of HMGB1 before the induction of KA further increased the expression of P-gp while pre-treatment with BoxA abolished this up-regulation. Next, the regulatory role of HMGB1 and its potential involved signal pathways were investigated in mouse microvascular endothelial bEnd.3 cells in vitro. Cells were treated with HMGB1, HMGB1 plus lipopolysaccharide from Rhodobacter sphaeroides (LPS-RS [toll-like receptor 4 (TLR4 antagonist], HMGB1 plus FPS-ZM1 [receptor for advanced glycation end products (RAGE inhibitor], HMGB1 plus SN50 [nuclear factor-kappa B (NF-κB inhibitor], or vehicle. Treatment with HMGB1 increased the expression levels of P-gp, TLR4, RAGE and the activation of NF-κB in bEnd.3 cells. These effects were inhibited by the pre-treatment with either LPS-RS or FPS-ZM1, and were abolished by the pre-treatment of SN50 or a combination treatment of both LPS-RS and FPS-ZM1. Luciferase reporter assays showed that exogenous expression of NF-κB p65 increased the promoter activity of multidrug resistance 1a (P-gp-encoding gene in endothelial cells. These data indicate that HMGB1 contributes to the overexpression of P-gp in mouse epileptic brain tissues via activation of TLR4/RAGE receptors and the downstream transcription factor NF-κB in brain microvascular endothelial cells.

  4. Concentration of Endogenous Secretory Receptor for Advanced Glycation End Products and Matrix Gla Protein in Controlled and Uncontrolled Type 2 Diabetes Mellitus Patients

    Directory of Open Access Journals (Sweden)

    Dwi Yuniati Daulay

    2013-04-01

    Full Text Available BACKGROUND: Advanced glycation end products (AGE and their receptor (RAGE system play an important role in the development of diabetic vascular complications. Recently, an endogenous secretory RAGE (esRAGE has been identified as a novel splice variant, which lacks the transmembrane domain and is secreted in human sera. Interestingly, it was reported that esRAGE binds AGE ligands and neutralizes AGE actions. Many studies have reported that diabetes mellitus correlates with vascular calcification event and increases progressively in uncontrolled diabetes. Matrix Gla Protein (MGP is known to act as an inhibitor in vascular calcification. The aim of this study was to observe progress of vascular calcification in uncontrolled diabetes patient by biochemical markers MGP as inhibitor in vascular calcification, via mechanism of AGEs. METHODS: This study was an observational study with cross sectional design on adult type 2 diabetic male patients who were defined by the 2011 Indonesian diabetes mellitus consensus criteria. RESULTS: The results of this study showed that there was a positive significant correlation between esRAGE and HbA1C (r=0.651, p=0.009, and negative correlation between MGP and HbA1C (r=-0.465, p=0.081 in controlled diabetes group. In uncontrolled diabetes group there was a positive significant correlation between MGP and HbA1C (r=0.350, p=0.023, despite the fact esRAGE showed no significant correlation with HbA1C. There was no significant difference in level of esRAGE and MGP in controlled and uncontrolled diabetes group, but MGP showed lower level in uncontrolled diabetes group, contrary to esRAGE that had higher concentration. CONCLUSIONS: In diabetes condition, complications of vascular calcification are caused by the mechanism of increased AGE formation represented by esRAGE. In diabetes control it is very important to keep the blood vessels from complications caused by vascular calcification. KEYWORDS: type 2 diabetes mellitus

  5. Involvement of formyl peptide receptors in receptor for advanced glycation end products (RAGE - and amyloid beta 1-42-induced signal transduction in glial cells

    Directory of Open Access Journals (Sweden)

    Slowik Alexander

    2012-11-01

    Full Text Available Abstract Background Recent studies suggest that the chemotactic G-protein-coupled-receptor (GPCR formyl-peptide-receptor-like-1 (FPRL1 and the receptor-for-advanced-glycation-end-products (RAGE play an important role in the inflammatory response involved in neurodegenerative disorders such as Alzheimer’s disease (AD. Therefore, the expression and co-localisation of mouse formyl peptide receptor (mFPR 1 and 2 as well as RAGE in an APP/PS1 transgenic mouse model using immunofluorescence and real-time RT-PCR were analysed. The involvement of rat or human FPR1/FPRL1 (corresponds to mFPR1/2 and RAGE in amyloid-β 1–42 (Aβ1-42-induced signalling were investigated by extracellular signal regulated kinase 1/2 (ERK1/2 phosphorylation. Furthermore, the cAMP level in primary rat glial cells (microglia and astrocytes and transfected HEK 293 cells was measured. Formyl peptide receptors and RAGE were inhibited by a small synthetic antagonist WRW4 and an inactive receptor variant delta-RAGE, lacking the intracytoplasmatic domains. Results We demonstrated a strong increase of mFPR1/2 and RAGE expression in the cortex and hippocampus of APP/PS1 transgenic mice co-localised to the glial cells. In addition, the Aβ1-42-induced signal transduction is dependant on FPRL1, but also on FPR1. For the first time, we have shown a functional interaction between FPRL1/FPR1 and RAGE in RAGE ligands S100B- or AGE-mediated signalling by ERK1/2 phosphorylation and cAMP level measurement. In addition a possible physical interaction between FPRL1 as well as FPR1 and RAGE was shown with co-immunoprecipitation and fluorescence microscopy. Conclusions The results suggest that both formyl peptide receptors play an essential role in Aβ1-42-induced signal transduction in glial cells. The interaction with RAGE could explain the broad ligand spectrum of formyl peptide receptors and their important role for inflammation and the host defence against infections.

  6. Inhibitory effect of different fennel (Foeniculum vulgare) samples and their phenolic compounds on formation of advanced glycation products and comparison of antimicrobial and antioxidant activities.

    Science.gov (United States)

    Salami, Maryam; Rahimmalek, Mehdi; Ehtemam, Mohammad Hossein

    2016-12-15

    In this study, antioxidant, antibacterial and antiglycation properties of methanolic extracts of 23 fennel samples were evaluated and their major compounds were determined using HPLC analysis. The anti-glycative activity of extracts was evaluated in the bovine serum albumin (BSA)/glucose system. The level of glycation, conformational alterations and protein binding to RAGE receptors were assessed by Congo red binding assay and a brown staining method. Among samples, Kh1 from Iran possessed the highest TFC (14.8mgQUEg(-1)), TPC (262mg/g DW) and antioxidant activity (IC50=76μg/ml). The HPLC results revealed high variation in 23 fennel samples according to their major flavonoid (quercetin, apigenin and rutin) and phenolic (chlorogenic, caffeic and 1,5-dicaffeoylquinic acid) compounds. The antibacterial activity of methanolic extracts against four food-borne pathogens was also assessed. The seed extracts of Kh1 and En samples showed moderate to good inhibitory activities (MICs=62.5-125μg/ml) against three bacteria, as well as high anti-glycative activity.

  7. Glycation of Wild-Type Apomyoglobin Induces Formation of Highly Cytotoxic Oligomeric Species.

    Science.gov (United States)

    Iannuzzi, Clara; Carafa, Vincenzo; Altucci, Lucia; Irace, Gaetano; Borriello, Margherita; Vinciguerra, Roberto; Sirangelo, Ivana

    2015-11-01

    Protein glycation is a non-enzymatic, irreversible modification of protein amino groups by reactive carbonyl species leading to the formation of advanced glycation end products (AGEs). Several proteins implicated in neurodegenerative diseases have been found to be glycated in vivo and the extent of glycation is related to the pathologies of the patients. Although it is now accepted that there is a direct correlation between AGEs formation and the development of neurodegenerative diseases related to protein misfolding and amyloid aggregation, several questions still remain unanswered: whether glycation is the triggering event or just an additional factor acting on the aggregation pathway. We have recently shown that glycation of the amyloidogenic W7FW14F apomyoglobin mutant significantly accelerates the amyloid fibrils formation providing evidence that glycation actively participates to the process. In the present study, to test if glycation can be considered also a triggering factor in amyloidosis, we evaluated the ability of different glycation agents to induce amyloid aggregation in the soluble wild-type apomyoglobin. Our results show that glycation covalently modifies apomyoglobin and induces conformational changes that lead to the formation of oligomeric species that are not implicated in amyloid aggregation. Thus, AGEs formation does not trigger amyloid aggregation in the wild-type apomyoglobin but only induce the formation of soluble oligomeric species able to affect cell viability. The molecular bases of cell toxicity induced by AGEs formed upon glycation of wild-type apomyoglobin have been also investigated.

  8. Advanced Glycation End Products Affect Osteoblast Proliferation and Function by Modulating Autophagy Via the Receptor of Advanced Glycation End Products/Raf Protein/Mitogen-activated Protein Kinase/Extracellular Signal-regulated Kinase Kinase/Extracellular Signal-regulated Kinase (RAGE/Raf/MEK/ERK) Pathway.

    Science.gov (United States)

    Meng, Hong-Zheng; Zhang, Wei-Lin; Liu, Fei; Yang, Mao-Wei

    2015-11-20

    The interaction between advanced glycation end products (AGEs) and receptor of AGEs (RAGE) is associated with the development and progression of diabetes-associated osteoporosis, but the mechanisms involved are still poorly understood. In this study, we found that AGE-modified bovine serum albumin (AGE-BSA) induced a biphasic effect on the viability of hFOB1.19 cells; cell proliferation was stimulated after exposure to low dose AGE-BSA, but cell apoptosis was stimulated after exposure to high dose AGE-BSA. The low dose AGE-BSA facilitates proliferation of hFOB1.19 cells by concomitantly promoting autophagy, RAGE production, and the Raf/MEK/ERK signaling pathway activation. Furthermore, we investigated the effects of AGE-BSA on the function of hFOB1.19 cells. Interestingly, the results suggest that the short term effects of low dose AGE-BSA increase osteogenic function and decrease osteoclastogenic function, which are likely mediated by autophagy and the RAGE/Raf/MEK/ERK signal pathway. In contrast, with increased treatment time, the opposite effects were observed. Collectively, AGE-BSA had a biphasic effect on the viability of hFOB1.19 cells in vitro, which was determined by the concentration of AGE-BSA and treatment time. A low concentration of AGE-BSA activated the Raf/MEK/ERK signal pathway through the interaction with RAGE, induced autophagy, and regulated the proliferation and function of hFOB1.19 cells.

  9. Vanillin restrains non-enzymatic glycation and aggregation of albumin by chemical chaperone like function.

    Science.gov (United States)

    Awasthi, Saurabh; Saraswathi, N T

    2016-06-01

    Vanillin a major component of vanilla bean extract is commonly used a natural flavoring agent. Glycation is known to induce aggregation and fibrillation of globular proteins such as albumin, hemoglobin. Here we report the inhibitory potential of vanillin toward early and advanced glycation modification and amyloid like aggregation of albumin based on the determination of both early and advanced glycation and conformational changes in albumin using circular dichroism. Inhibition of aggregation and fibrillation of albumin was determined based on amyloid specific dyes i.e., Congo red and Thioflavin T and microscopic imaging. It was evident that vanillin restrains glycation of albumin and exhibits protective effect toward its native conformation.

  10. Non-enzymatic Glycation of Almond Cystatin Leads to Conformational Changes and Altered Activity.

    Science.gov (United States)

    Siddiqui, Azad A; Sohail, Aamir; Bhat, Sheraz A; Rehman, Md T; Bano, Bilqees

    2015-01-01

    The non-enzymatic reaction between proteins and reducing sugars, known as glycation, leads to the formation of inter and intramolecular cross-links of proteins. Stable end products called as advanced Maillard products or advanced glycation end products (AGEs) have received tremendous attention since last decades. It was suggested that the formation of AGEs not only modify the conformation of proteins but also induces altered biological activity. In this study, cystatin purified from almond was incubated with three different sugars namely D-ribose, fructose and lactose to monitor the glycation process. Structural changes induced in cystatin on glycation were studied using UV-visible spectroscopy, fluorescence spectroscopy, CD and FTIR techniques. Glycated cystatin was found to migrate slower on electrophoresis as compared to control cystatin. Biological activity data of glycated cystatin showed that D-ribose was most effective in inducing conformational changes with maximum altered activity.

  11. D-Ribose Induces Cellular Protein Glycation and Impairs Mouse Spatial Cognition

    OpenAIRE

    Chanshuai Han; Yang Lu; Yan Wei; Ying Liu; Rongqiao He

    2011-01-01

    BACKGROUND: D-ribose, an important reducing monosaccharide, is highly active in the glycation of proteins, and results in the rapid production of advanced glycation end products (AGEs) in vitro. However, whether D-ribose participates in glycation and leads to production of AGEs in vivo still requires investigation. METHODOLOGY/PRINCIPAL FINDINGS: Here we treated cultured cells and mice with D-ribose and D-glucose to compare ribosylation and glucosylation for production of AGEs. Treatment with...

  12. Increased cation conductance in human erythrocytes artificially aged by glycation.

    Science.gov (United States)

    Kucherenko, Yuliya V; Bhavsar, Shefalee K; Grischenko, Valentin I; Fischer, Uwe R; Huber, Stephan M; Lang, Florian

    2010-06-01

    Excessive glucose concentrations foster glycation and thus premature aging of erythrocytes. The present study explored whether glycation-induced erythrocyte aging is paralleled by features of suicidal erythrocyte death or eryptosis, which is characterized by cell membrane scrambling with subsequent phosphatidylserine exposure at the cell surface and cell shrinkage. Both are triggered by increases of cytosolic Ca(2+) concentration ([Ca(2+)](i)), which may result from activation of Ca(2+) permeable cation channels. Glycation was accomplished by exposure to high glucose concentrations (40 and 100 mM), phosphatidylserine exposure estimated from annexin binding, cell shrinkage from decrease of forward scatter, and [Ca(2+)](i) from Fluo3-fluorescence in analysis via fluorescence-activated cell sorter. Cation channel activity was determined by means of whole-cell patch clamp. Glycation of total membrane proteins, immunoprecipitated TRPC3/6/7, and immunoprecipitated L-type Ca(2+) channel proteins was estimated by Western blot testing with polyclonal antibodies used against advanced glycation end products. A 30-48-h exposure of the cells to 40 or 100 mM glucose in Ringer solution (at 37 degrees C) significantly increased glycation of membrane proteins, hemoglobin (HbA(1c)), TRPC3/6/7, and L-type Ca(2+) channel proteins, enhanced amiloride-sensitive, voltage-independent cation conductance, [Ca(2+)](i), and phosphatidylserine exposure, and led to significant cell shrinkage. Ca(2+) removal and addition of Ca(2+) chelator EGTA prevented the glycation-induced phosphatidylserine exposure and cell shrinkage after glycation. Glycation-induced erythrocyte aging leads to eryptosis, an effect requiring Ca(2+) entry from extracellular space.

  13. Products by Glycation Process

    Directory of Open Access Journals (Sweden)

    Liliana Ortega

    2015-01-01

    Full Text Available The antioxidant properties of sweet and acid whey products were incremented by polymerization of their proteins by glycation of whey protein concentrates (WPC and their hydrolyzates (WPCH with ribose and glucose in individual experiments under similar concentration. Heating at 50°C during 20 h maximum and pH 7 and pH 9 were used in all tests. The higher activity was found in WPC glycosylates products with ribose at pH 7 and heating during 10–15 h. In comparable form, antioxidant activity in WPCH was incremented by prior hydrolysis to glycation with 25–45% of hydrolysis degree. Further functional properties of whey proteins (solubility, emulsion, and foam were also improved by the polymerization with ribose. The color of polymerized products due to Maillard reactions was associated with antioxidant activity of each compound; however comparative color in glycosylates products with glucose and ribose did not show this effect.

  14. Inactivation of cellular enzymes by carbonyls and protein-bound glycation/glycoxidation products

    DEFF Research Database (Denmark)

    Morgan, Philip E; Dean, Roger T; Davies, Michael Jonathan

    2002-01-01

    Diabetic plasma contains elevated levels of glucose and various low-molecular-weight carbonyl compounds derived from the metabolism of glucose and related materials. These compounds react with protein side chains (Arg, Lys, Cys, and His) to give glycated materials and advanced glycation end produ...

  15. Similarity of the yellow chromophores isolated from human cataracts with those from ascorbic acid-modified calf lens proteins: evidence for ascorbic acid glycation during cataract formation.

    Science.gov (United States)

    Cheng, R; Lin, B; Lee, K W; Ortwerth, B J

    2001-07-27

    chromophores in brunescent lenses represent advanced glycation endproducts (AGEs) probably due to ascorbic acid glycation in vivo.

  16. 糖基化终末产物及其受体在胃肠道中的分布%Distribution of advanced glycation end products and their receptor in the gastrointestinal tract

    Institute of Scientific and Technical Information of China (English)

    陈朋民; 赵静波; Hans Gregersen

    2012-01-01

    目的:研究糖基化终末产物(advanced glycation end products,AGE)及其受体(receptor for advanced glycation end products,RAGE)在胃肠道中的分布,为进一步探索其在慢性糖尿病胃肠功能紊乱中的作用奠定基础.方法:分别对成年Wistar大鼠食管、胃、十二指肠、空肠、回肠、结肠及直肠组织进行AGE及RAGE免疫组织化学染色.结果:(1)食管:AGE及RAGE主要分布在横纹肌的肌细胞及黏膜的鳞状上皮细胞;(2)胃:AGE在壁细胞为强阳性.RAGE在主细胞、肥大细胞、神经细胞为强阳性,在壁细胞为中等强度阳性,在表面黏液细胞为弱阳性;(3)小肠:AGE及RAGE在绒毛及固有层上皮细胞为阳性或强阳性.RAGE在肠道的神经细胞亦为强阳性;(4)结肠及直肠:AGE及RAGE在黏膜上皮细胞为弱阳性,RAGE在神经细胞为强阳性.结论:AGE及RAGE广泛分布于肠道上皮细胞及食管的横纹肌细胞,AGE亦分布于胃的壁细胞,RAGE亦分布于胃的壁细胞、主细胞、表面黏液细胞、肥大细胞及胃肠道的神经细胞.%AIM: To investigate the distribution of advanced glycation end products (AGEs) and their receptor (RAGE) in the gastrointestinal (GI) tract to provide a basis for further study of the association between AGE/RAGE and diabetic GI dysfunction. METHODS: The distribution of AGEs [N epsilon-(c arboxymethyl) lysine and N epsilon-(carboxyethyl) lysine] and RAGE were detected in the esopha-geal, gastric, duodenal, jejunal, ileal, colonic and rectal tissues of normal adult Wistar rats using immunohistochemistry. RESULTS: In the esophagus, AGEs and RAGE were mainly distributed in striated muscle cells and squamous epithelial cells. In the stomach, AGEs were mainly distributed in parietal cells, and RAGE was strongly expressed in chief cells, mast cells and neurons in ganglia, moderately in parietal cells, and mildly in surface mucous cells. In the intestine, colon and rectum, AGEs and RAGE were distributed in mucosal

  17. Quantitative analysis of glycated proteins.

    Science.gov (United States)

    Priego-Capote, Feliciano; Ramírez-Boo, María; Finamore, Francesco; Gluck, Florent; Sanchez, Jean-Charles

    2014-02-07

    The proposed protocol presents a comprehensive approach for large-scale qualitative and quantitative analysis of glycated proteins (GP) in complex biological samples including biological fluids and cell lysates such as plasma and red blood cells. The method, named glycation isotopic labeling (GIL), is based on the differential labeling of proteins with isotopic [(13)C6]-glucose, which supports quantitation of the resulting glycated peptides after enzymatic digestion with endoproteinase Glu-C. The key principle of the GIL approach is the detection of doublet signals for each glycated peptide in MS precursor scanning (glycated peptide with in vivo [(12)C6]- and in vitro [(13)C6]-glucose). The mass shift of the doublet signals is +6, +3 or +2 Da depending on the peptide charge state and the number of glycation sites. The intensity ratio between doublet signals generates quantitative information of glycated proteins that can be related to the glycemic state of the studied samples. Tandem mass spectrometry with high-energy collisional dissociation (HCD-MS2) and data-dependent methods with collision-induced dissociation (CID-MS3 neutral loss scan) are used for qualitative analysis.

  18. Blood proteome characterization of the interplay between glycation and aspirin-mediated acetylation in vitro and in diabetic patients

    OpenAIRE

    Finamore, Francesco

    2016-01-01

    Among post-translational modifications, non-enzymatic glycation is of particular relevance, since it plays a pivotal role in the development of long-term diabetic complications. Beside continuous advances in treatment of those deleterious effects, aspirin was shown to prevent proteins from excessive glycation. However, the interplay between aspirin-induced acetylation and protein glycation was poorly investigated. In this project we studied an in vitro model of the influence between high gluc...

  19. Morphological adaptation of muscle collagen and receptor of advanced glycation end product (RAGE) in osteoarthritis patients with 12 weeks of resistance training: influence of anti-inflammatory or glucosamine treatment.

    Science.gov (United States)

    Mattiello-Sverzut, Ana Claudia; Petersen, Susanne G; Kjaer, Michael; Mackey, Abigail L

    2013-09-01

    The aim of this study was to investigate the effect of 12-week resistance training on morphological presence of collagen and RAGE (receptor for advanced glycation end products) in skeletal muscle of patients with knee osteoarthritis (OA). Little is known about the influence of exercise on the skeletal muscle matrix that supports joints affected by OA mainly when it is associated with medication taken by OA patients (non-steroid anti-inflammatory drugs (NSAID) and glucosamine). A biopsy was collected from the vastus lateralis muscle in all patients before and after 12-week period of training. The patients (age 55-69 years) were divided into three groups, treated with NSAID, glucosamine or placebo. In addition, the muscle samples were analysed by immunohistochemistry for collagen types, RAGE and capillaries ratio. An increment in immunoreactivity for type IV collagen after the training period was observed in 72 % of all biopsies when compared with their respective baseline samples. Reduced immunoreactivity of collagen type I was observed in all patients treated with glucosamine. A significant increase with training in the amount of RAGE was detected in the placebo group only (p muscle fibres after 12 weeks of resistance training. Glucosamine with training appeared to attenuate RAGE accumulation more than was seen with NSAID or placebo in skeletal muscle of OA patients.

  20. Association of advanced glycation end products with A549 cells, a human pulmonary epithelial cell line, is mediated by a receptor distinct from the scavenger receptor family and RAGE.

    Science.gov (United States)

    Nakano, Nahoko; Fukuhara-Takaki, Kaori; Jono, Tadashi; Nakajou, Keisuke; Eto, Nobuaki; Horiuchi, Seikoh; Takeya, Motohiro; Nagai, Ryoji

    2006-05-01

    Cellular interactions with advanced glycation end products (AGE)-modified proteins are known to induce several biological responses, not only endocytic uptake and degradation, but also the induction of cytokines and growth factors, combined responses that may be linked to the development of diabetic vascular complications. In this study we demonstrate that A549 cells, a human pulmonary epithelial cell line, possess a specific binding site for AGE-modified bovine serum albumin (AGE-BSA) (K(d) = 27.8 nM), and additionally for EN-RAGE (extracellular newly identified RAGE binding protein) (K(d) = 118 nM). Western blot and RT-PCR analysis showed that RAGE (receptor for AGE) is highly expressed on A549 cells, while the expression of other known AGE-receptors such as galectin-3 and SR-A (class A scavenger receptor), are below the level of detection. The binding of (125)I-AGE-BSA to these cells is inhibited by unlabeled AGE-BSA, but not by EN-RAGE. In contrast, the binding of (125)I-EN-RAGE is significantly inhibited by unlabeled EN-RAGE and soluble RAGE, but not by AGE-BSA. Our results indicate that A549 cells possess at least two binding sites, one specific for EN-RAGE and the other specific for AGE-BSA. The latter receptor on A549 cells is distinct from the scavenger receptor family and RAGE.

  1. Nifedipine, a calcium channel blocker, inhibits advanced glycation end product (AGE)-elicited mesangial cell damage by suppressing AGE receptor (RAGE) expression via peroxisome proliferator-activated receptor-gamma activation

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Takanori [Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011 (Japan); Yamagishi, Sho-ichi, E-mail: shoichi@med.kurume-u.ac.jp [Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011 (Japan); Takeuchi, Masayoshi [Department of Pathophysiological Science, Faculty of Pharmaceutical Science, Hokuriku University, Kanazawa (Japan); Ueda, Seiji; Fukami, Kei; Okuda, Seiya [Department of Medicine, Kurume University School of Medicine, Kurume (Japan)

    2009-07-24

    The interaction between advanced glycation end products (AGE) and their receptor RAGE mediates the progressive alteration in renal architecture and loss of renal function in diabetic nephropathy. Oxidative stress generation and inflammation also play a central role in diabetic nephropathy. This study investigated whether and how nifedipine, a calcium channel blocker (CCB), blocked the AGE-elicited mesangial cell damage in vitro. Nifedipine, but not amlodipine, a control CCB, down-regulated RAGE mRNA levels and subsequently reduced reactive oxygen species (ROS) generation in AGE-exposed mesangial cells. AGE increased mRNA levels of vascular cell adhesion molecule-1 (VCAM-1) and induced monocyte chemoattractant protein-1 (MCP-1) production in mesangial cells, both of which were prevented by the treatment with nifedipine, but not amlodipine. The beneficial effects of nifedipine on AGE-exposed mesangial cells were blocked by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma} (PPAR-{gamma}). Although nifedipine did not affect expression levels of PPAR-{gamma}, it increased the PPAR-{gamma} transcriptional activity in mesangial cells. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-inflammatory agent against AGE by suppressing RAGE expression in cultured mesangial cells via PPAR-{gamma} activation.

  2. Advanced Glycation End Products Impair Glucose-Stimulated Insulin Secretion of a Pancreatic β-Cell Line INS-1-3 by Disturbance of Microtubule Cytoskeleton via p38/MAPK Activation

    Directory of Open Access Journals (Sweden)

    Jia You

    2016-01-01

    Full Text Available Advanced glycation end products (AGEs are believed to be involved in diverse complications of diabetes mellitus. Overexposure to AGEs of pancreatic β-cells leads to decreased insulin secretion and cell apoptosis. Here, to understand the cytotoxicity of AGEs to pancreatic β-cells, we used INS-1-3 cells as a β-cell model to address this question, which was a subclone of INS-1 cells and exhibited high level of insulin expression and high sensitivity to glucose stimulation. Exposed to large dose of AGEs, even though more insulin was synthesized, its secretion was significantly reduced from INS-1-3 cells. Further, AGEs treatment led to a time-dependent increase of depolymerized microtubules, which was accompanied by an increase of activated p38/MAPK in INS-1-3 cells. Pharmacological inhibition of p38/MAPK by SB202190 reversed microtubule depolymerization to a stabilized polymerization status but could not rescue the reduction of insulin release caused by AGEs. Taken together, these results suggest a novel role of AGEs-induced impairment of insulin secretion, which is partially due to a disturbance of microtubule dynamics that resulted from an activation of the p38/MAPK pathway.

  3. Advanced glycation end product 3 (AGE3) suppresses the mineralization of mouse stromal ST2 cells and human mesenchymal stem cells by increasing TGF-β expression and secretion.

    Science.gov (United States)

    Notsu, Masakazu; Yamaguchi, Toru; Okazaki, Kyoko; Tanaka, Ken-ichiro; Ogawa, Noriko; Kanazawa, Ippei; Sugimoto, Toshitsugu

    2014-07-01

    In diabetic patients, advanced glycation end products (AGEs) cause bone fragility because of deterioration of bone quality. We previously showed that AGEs suppressed the mineralization of mouse stromal ST2 cells. TGF-β is abundant in bone, and enhancement of its signal causes bone quality deterioration. However, whether TGF-β signaling is involved in the AGE-induced suppression of mineralization during the osteoblast lineage remains unknown. We therefore examined the roles of TGF-β in the AGE-induced suppression of mineralization of ST2 cells and human mesenchymal stem cells. AGE3 significantly (P mineralization in both cell types, whereas transfection with small interfering RNA for the receptor for AGEs (RAGEs) significantly (P mineralization in both cell types. In contrast, SD208 intensified AGE3-induced suppression of cell proliferation as well as AGE3-induced apoptosis in proliferating ST2 cells. These findings indicate that, after cells become confluent, AGE3 partially inhibits the differentiation and mineralization of osteoblastic cells by binding to RAGE and increasing TGF-β expression and secretion. They also suggest that TGF-β adversely affects bone quality not only in primary osteoporosis but also in diabetes-related bone disorder.

  4. Mangiferin suppressed advanced glycation end products (AGEs) through NF-κB deactivation and displayed anti-inflammatory effects in streptozotocin and high fat diet-diabetic cardiomyopathy rats.

    Science.gov (United States)

    Hou, Jun; Zheng, Dezhi; Fung, Gabriel; Deng, Haoyu; Chen, Lin; Liang, Jiali; Jiang, Yan; Hu, Yonghe

    2016-03-01

    Given the importance of the aggregation of advanced glycation end products (AGEs) and cardiac inflammation in the onset and progression of diabetic cardiomyopathy (DCM), our objective in this study was to demonstrate the cardioprotective effect of mangiferin, an antidiabetic and anti-inflammatory agent, on diabetic rat model. The DCM model was established by a high-fat diet and a low dose of streptozotocin. DCM rats were treated orally with mangiferin (20 mg/kg) for 16 weeks. Serum and left ventricular myocardium were collected for determination of inflammatory cytokines. AGEs mRNA and protein expression of nuclear factor kappa B (NF-κB) and receptor for AGEs (RAGE) in myocardium were assayed by real-time PCR and Western blot. ROS levels were measured by dihydroethidium fluorescence staining. NF-κB binding activity was assayed by TransAM NF-κB p65 ELISA kit. Chronic treatment with mangiferin decreased the levels of myocardial enzymes (CK-MB, LDH) and inflammatory mediators (TNF-α, IL-1β). Meanwhile, NF-κB is inhibited by the reduction of nuclear translocation of p65 subunit, and mangiferin reduced AGE production and decreased the mRNA and protein expression of RAGE in DCM rats. Our data indicated that mangiferin could significantly ameliorate DCM by preventing the release of inflammatory cytokines, and inhibiting ROS accumulation, AGE/RAGE production, and NF-κB nuclear translocation, suggesting that mangiferin treatment might be beneficial in DCM.

  5. Metformin inhibits advanced glycation end products (AGEs)-induced growth and VEGF expression in MCF-7 breast cancer cells by suppressing AGEs receptor expression via AMP-activated protein kinase.

    Science.gov (United States)

    Ishibashi, Y; Matsui, T; Takeuchi, M; Yamagishi, S

    2013-05-01

    Metformin use has been reported to decrease breast cancer incidence and mortality in diabetic patients. We have previously shown that advanced glycation end products (AGEs) and their receptor (RAGE) interaction stimulate growth and/or migration of pancreatic cancer and melanoma cells. However, effects of metformin on AGEs-RAGE axis in breast cancers remain unknown. We examined here whether and how metformin could block the AGEs-induced growth and vascular endothelial growth factor (VEGF) expression in MCF-7 breast cancer cells. Cell proliferation was measured with an electron coupling reagent WST-1 based colorimetric assay. Gene expression level was evaluated by real-time reverse-transcription polymerase chain reactions. AGEs significantly increased cell proliferation of MCF-7 cells, which was completely prevented by the treatment with 0.01 or 0.1 mM metformin or anti-RAGE antibodies. Furthermore, metformin at 0.01 mM completely suppressed the AGEs-induced upregulation of RAGE and VEGF mRNA levels in MCF-7 cells. An inhibitor of AMP-activated protein kinase, compound C significantly blocked the growth-inhibitory and RAGE and VEGF suppressing effects of metformin in AGEs-exposed MCF-7 cells. Our present study suggests that metformin could inhibit the AGEs-induced growth and VEGF expression in MCF-7 breast cancer cells by suppressing RAGE gene expression via AMP-activated protein kinase pathway. Metformin may protect against breast cancer expansion in diabetic patients by blocking the AGEs-RAGE axis.

  6. Protein glycation inhibitors from the fruiting body of Phellinus linteus.

    Science.gov (United States)

    Lee, Yeon Sil; Kang, Young-Hee; Jung, Ju-Young; Lee, Sanghyun; Ohuchi, Kazuo; Shin, Kuk Hyun; Kang, Il-Jun; Park, Jung Han Yoon; Shin, Hyun-Kyung; Lim, Soon Sung

    2008-10-01

    To characterize active principles for prevention and treatment of diabetic complications, the isolation of protein glycation inhibitors from the fruiting body of Phellinus linteus was conducted in vitro using the model systems of hemoglobin-delta-gluconolactone (early stage), bovine serum albumin-methylglyoxal (middle stage), and N(alpha)-acetyl-glycyl-lysine methyl ester-D-ribose (last stage) assays. Nine compounds were isolated from the active ethylacetate fraction of the fruiting body and identified as protocatechuic acid (1), protocatechualdehyde (2), caffeic acid (3), ellagic acid (4), hispidin (5), davallialactone (6), hypholomine B (7), interfungins A (8), and inoscavin A (9) by spectroscopic analyses. At the early stage of protein glycation, compounds 6, 8, and 9 exhibited inhibitory activity on hemoglobin A(1C) formation. For the middle stage, compounds 2, 6, and 9 showed a significant inhibitory effect on methylglyoxal-medicated protein modification and their IC(50) values were 144.28, 213.15, and 158.66 muM, respectively. At the last stage of glycation, compound 8 was found to be a potent inhibitor of the cross-linking of proteins, which was more effective than that of aminoguanidine, a well-known inhibitor for advanced glycation end products. Consequently, compound 8 showed the most potent inhibitory effects at each stage of protein glycation. This mechanism may help to provide a protective effect against hyperglycemia-mediated protein damage.

  7. Role of Glyoxalase 1 (Glo1 and methylglyoxal (MG in behavior: recent advances and mechanistic insights

    Directory of Open Access Journals (Sweden)

    Margaret G Distler

    2012-11-01

    Full Text Available Glyoxalase 1 (GLO1 is a ubiquitous cellular enzyme that participates in the detoxification of methylglyoxal (MG, a cyotoxic byproduct of glycolysis that induces protein modification (advanced glycation end-products, AGEs, oxidative stress, and apoptosis. The concentration of MG is elevated under high-glucose conditions, such as diabetes. As such, GLO1 and MG have been implicated in the pathogenesis of diabetic complications. Recently, findings have linked GLO1 to numerous behavioral phenotypes, including psychiatric diseases (anxiety, depression, schizophrenia, and autism and pain. This review highlights GLO1’s association with behavioral phenotypes, describes recent discoveries that have elucidated the underlying mechanisms, and identifies opportunities for future research.

  8. 马钱苷对糖基化终末产物诱导足细胞损伤的保护作用%Protective effect of loganin on podocyte injury induced by advanced glycation end products

    Institute of Scientific and Technical Information of China (English)

    吴云皓; 陈玉萍; 吕兴; 周芷若; 沈红胜; 戴国英; 许惠琴

    2016-01-01

    Aim To explore the protective effect of lo-ganin ( an active component in Cornus officinalis ) on podocyte injury induced by advanced glycation end products ( AGEs) and its possible mechanism. Meth-ods Mouse podocytes were cultured in vitro and di-vided into Normal group, model group ( AGEs group) , loganin group and aminoguanidine group ( set as posi-tive control) . After being incubated with loganin( final concentrations are 0. 1, 1, 10 μmol · L-1 ) for 1 h, podocytes were stimulated by AGEs of 100 mg · L-1 for 24 h. Then, the cell viability was measured by u-sing MTT method. Podocytes apoptosis was evaluated by Hoechst33342/PI staining and flow cytometry. Re-ceptors of advanced glycation end products ( RAGE ) ,desmin and apoptosis-related protein like Bax, Bcl-2, cleaved caspase-3 in podocytes were detected by Western blot. Results Loganin ameliorated podocyte injury induced by AGEs, down-regulated the expression of desmin and RAGE. Loganin also reduced the apoptotic rate of podocytes and decreased the ratio of Bax/ Bcl-2 and the expression of pro-apoptotic protein cleaved caspase-3 in podocytes. Conclusion Loganin could ameliorate podocyte injury, and its mechanism may be related to the decrease of the expression of RAGE and inhibition of the apoptotic pathway.%目的:探讨山茱萸环烯醚萜苷特征性成分马钱苷对糖基化终末产物( AGEs)诱导肾脏足细胞损伤的保护作用及其机制。方法体外培养小鼠肾小球足细胞,分为空白对照组、模型组( AGEs组)、马钱苷组,并设氨基胍组作为阳性对照。 MTT法检测马钱苷对足细胞存活率的影响;Hoechst 33342/PI双染观察足细胞凋亡情况,流式细胞仪检测细胞凋亡率;Western blot法检测足细胞AGEs受体( RAGE )、足细胞损伤标志蛋白 desmin 以及凋亡相关蛋白 bax、bcl-2、cleaved caspase-3的表达。结果马钱苷能够抑制AGEs导致的足细胞损伤,下调足细胞Desmin、RAGE蛋白的表达,明显降

  9. Glucagon-like peptide-1 receptor agonist inhibits asymmetric dimethylarginine generation in the kidney of streptozotocin-induced diabetic rats by blocking advanced glycation end product-induced protein arginine methyltranferase-1 expression.

    Science.gov (United States)

    Ojima, Ayako; Ishibashi, Yuji; Matsui, Takanori; Maeda, Sayaka; Nishino, Yuri; Takeuchi, Masayoshi; Fukami, Kei; Yamagishi, Sho-ichi

    2013-01-01

    Advanced glycation end products (AGEs) and their receptor (RAGE) play a role in diabetic nephropathy. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, contributes to diabetic nephropathy. We have found that glucagon-like peptide-1 (GLP-1) inhibits the AGE-induced inflammatory reactions in endothelial cells. However, effects of GLP-1 on the AGE-RAGE-ADMA axis are unknown. This study examined the effects of GLP-1 on reactive oxygen species (ROS) generation, gene expression of protein arginine methyltransfetase-1 (PRMT-1), an enzyme that mainly generates ADMA, and ADMA levels in human proximal tubular cells. Streptozotocin-induced diabetic rats received continuous i.p. infusion of 0.3 μg of vehicle or 1.5 μg of the GLP-1 analog exendin-4 per kilogram of body weight for 2 weeks. We further investigated whether and how exendin-4 treatment reduced ADMA levels and renal damage in streptozotocin-induced diabetic rats. GLP-1 inhibited the AGE-induced RAGE and PRMT-1 gene expression, ROS, and ADMA generation in tubular cells, which were blocked by small-interfering RNAs raised against GLP-1 receptor. Exendin-4 treatment decreased gene expression of Rage, Prmt-1, Icam-1, and Mcp-1 and ADMA level; reduced urinary excretions of 8-hydroxy-2'-deoxyguanosine and albumin; and improved histopathologic changes of the kidney in diabetic rats. Our present study suggests that GLP-1 receptor agonist may inhibit the AGE-RAGE-mediated ADMA generation by suppressing PRMT-1 expression via inhibition of ROS generation, thereby protecting against the development and progression of diabetic nephropathy.

  10. Effects of high glucose and advanced glycation end products on the expressions of sclerostin and RANKL as well as apoptosis in osteocyte-like MLO-Y4-A2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Ken-ichiro, E-mail: ken1nai@med.shimane-u.ac.jp; Yamaguchi, Toru, E-mail: yamaguch@med.shimane-u.ac.jp; Kanazawa, Ippei, E-mail: ippei.k@med.shimane-u.ac.jp; Sugimoto, Toshitsugu, E-mail: sugimoto@med.shimane-u.ac.jp

    2015-05-29

    In diabetes mellitus (DM), high glucose (HG) and advanced glycation end products (AGEs) are involved in bone quality deterioration. Osteocytes produce sclerostin and receptor activator of nuclear factor-kB ligand (RANKL) and regulate osteoblast and osteoclast function. However, whether HG or AGEs directly affect osteocytes and regulate sclerostin and RANKL production is unknown. Here, we examined the effects of HG, AGE2, and AGE3 on the expression of sclerostin and RANKL and on apoptosis in osteocyte-like MLO-Y4-A2 cells. Treatment of the cells with 22 mM glucose, 100 μg/mL either AGE2 or AGE3 significantly increased the expression of sclerostin protein and mRNA; however, both AGEs, but not glucose, significantly decreased the expression of RANKL protein and mRNA. Moreover, treatment of the cells with HG, AGE2, or AGE3 for 72 h induced significant apoptosis. These detrimental effects of HG, AGE2, and AGE3 on sclerostin and RANKL expressions and on apoptosis were antagonized by pretreatment of the cells with 10{sup −8} M human parathyroid hormone (PTH)-(1–34). Thus, HG and AGEs likely suppress bone formation by increasing sclerostin expression in osteocytes, whereas AGEs suppress bone resorption by decreasing RANKL expression. Together, these processes may cause low bone turnover in DM. In addition, HG and AGEs may cause cortical bone deterioration by inducing osteocyte apoptosis. PTH may effectively treat these pathological processes and improve osteocyte function. - Highlights: • AGEs are involved in bone quality deterioration in diabetes mellitus (DM). • AGEs increased sclerostin as well as apoptosis, and decreased RANKL in osteocytes. • The effects of AGEs on osteocyte function were antagonized by human PTH-(1–34). • AGEs may cause low bone turnover and cortical porosity in DM. • PTH may be effective in bone quality deterioration by improving osteocyte function.

  11. N(ε)-Carboxymethyllysine (CML), a Maillard reaction product, stimulates serotonin release and activates the receptor for advanced glycation end products (RAGE) in SH-SY5Y cells.

    Science.gov (United States)

    Holik, Ann-Katrin; Rohm, Barbara; Somoza, Mark M; Somoza, Veronika

    2013-07-01

    Maillard reaction products, which are formed in highly thermally treated foods, are commonly consumed in a Western diet. In this study, we investigated the impact of N(ε)-carboxymethyllysine (CML), a well-characterized product of the Maillard reaction, on the gene regulation of the human neuroblastoma cell line SH-SY5Y. Pathway analysis of data generated from customized DNA microarrays revealed 3 h incubation with 50 μM and 500 μM CML to affect serotonin receptor expression. Further experiments employing qRT-PCR showed an up-regulation of serotonin receptors 2A, 1A and 1B after 0.25 h and 3 h. In addition, 500 μM CML increased serotonin release, thus showing effects of CML not only at a genetic, but also at a functional level. Intracellular calcium mobilization, which mediates serotonin release, was increased by CML at concentrations of 0.05-500 μM. Since calcium mobilization has been linked to the activation of the receptor for advanced glycation end products (RAGE), we further investigated the effects of CML on RAGE expression. RAGE was found to be up-regulated after incubation with 500 μM CML for 0.25 h. Co-incubation with the calcium blocker neomycin for 0.25 h blocked the up-regulation of RAGE and the serotonin receptors 2A, 1A and 1B. These results indicate a possible link between a CML-induced calcium-mediated serotonin release and RAGE.

  12. Advanced glycation end products:novel target for treating diabetic nephropathy%晚期糖基化终末产物:糖尿病肾病治疗的新靶点

    Institute of Scientific and Technical Information of China (English)

    杜世春; 苏青

    2012-01-01

    Advanced glycation end products (AGEs) increased or accumulated in the body may get rise to cell dysfunction and promote diabetic microvascular complications,especially the development of diabetic nephropathy (DN).AGEs can cause the functional and structural changes of the kidney.Though focusing on different points of signal pathway,a number of new agents,such as inhibitors and breakers of AGEs,receptor antagonists for AGEs and inhibitors to the signal transduction pathway after AGEs receptor,can decrease the negative effect of AGEs on target organs and play therapeutic roles in DN.%晚期糖基化终末产物(AGEs)在体内的增加、蓄积会引起各种细胞功能障碍,促进糖尿病微血管并发症特别是糖尿病肾病的发生和发展.AGEs可引起肾脏功能障碍和结构改变.针对AGEs的药物如抑制AGEs形成的药物、AGEs交联裂解剂、阻断AGEs及其受体相互作用的药物、抑制AGEs受体的表达及其下游路径的药物,分别作用于不同的信号通路环节,但都具有减少AGEs对靶器官损伤的作用,对糖尿病肾病具有一定的治疗作用.

  13. Glycated hemoglobin and its spinoffs: Cardiovascular disease markers or risk factors?

    Institute of Scientific and Technical Information of China (English)

    Jumana; Saleh

    2015-01-01

    Atherosclerosis is a major complication of diabetes, increasing the risk of cardiovascular related morbidities and mortalities. The hallmark of diabetes is hyperglycemia which duration is best predicted by elevated glycated haemoglobin A1C(Hb A1C) levels. Diabetic complications are usually attributed to oxidative stress associated with glycation of major structural and functional proteins. This non-enzymatic glycation of long lived proteins such as collagen, albumin, fibrinogen, liver enzymes and globulins result in the formation of early and advanced glycation end products(AGEs) associated with the production of myriads of free radicles and oxidants that have detrimental effects leading to diabetic complications. AGEs have been extensively discussed in the literature as etiological factors in the advancement of atherogenic events. Mechanisms described include the effects of glycation on protein structure and function that lead to defective receptor binding, impairment of immune system and enzyme function and alteration of basement membrane structural integrity. Hemoglobin(Hb) is a major circulating protein susceptible to glycation. Glycated Hb, namely Hb A1 C is used as a useful tool in the diagnosis of diabetes progression. Many studies have shown strong positive associations between elevated Hb A1 C levels and existing cardiovascular disease and major risk factors. Also, several studies presented Hb A1 C as an independent predictor of cardiovascular risk. In spite of extensive reports on positive associations, limited evidence is available considering the role of glycated Hb in the etiology of atherosclerosis. This editorial highlights potential mechanisms by which glycated hemoglobin may contribute, as a causative factor, to the progression of atherosclerosis in diabetics.

  14. Glycated hemoglobin and its spinoffs: Cardiovascular disease markers or risk factors?

    Science.gov (United States)

    Saleh, Jumana

    2015-08-26

    Atherosclerosis is a major complication of diabetes, increasing the risk of cardiovascular related morbidities and mortalities. The hallmark of diabetes is hyperglycemia which duration is best predicted by elevated glycated haemoglobin A1C (HbA1C) levels. Diabetic complications are usually attributed to oxidative stress associated with glycation of major structural and functional proteins. This non-enzymatic glycation of long lived proteins such as collagen, albumin, fibrinogen, liver enzymes and globulins result in the formation of early and advanced glycation end products (AGEs) associated with the production of myriads of free radicles and oxidants that have detrimental effects leading to diabetic complications. AGEs have been extensively discussed in the literature as etiological factors in the advancement of atherogenic events. Mechanisms described include the effects of glycation on protein structure and function that lead to defective receptor binding, impairment of immune system and enzyme function and alteration of basement membrane structural integrity. Hemoglobin (Hb) is a major circulating protein susceptible to glycation. Glycated Hb, namely HbA1C is used as a useful tool in the diagnosis of diabetes progression. Many studies have shown strong positive associations between elevated HbA1C levels and existing cardiovascular disease and major risk factors. Also, several studies presented HbA1C as an independent predictor of cardiovascular risk. In spite of extensive reports on positive associations, limited evidence is available considering the role of glycated Hb in the etiology of atherosclerosis. This editorial highlights potential mechanisms by which glycated hemoglobin may contribute, as a causative factor, to the progression of atherosclerosis in diabetics.

  15. Glycation of human cortical and cancellous bone captures differences in the formation of Maillard reaction products between glucose and ribose.

    Science.gov (United States)

    Sroga, Grażyna E; Siddula, Alankrita; Vashishth, Deepak

    2015-01-01

    To better understand some aspects of bone matrix glycation, we used an in vitro glycation approach. Within two weeks, our glycation procedures led to the formation of advanced glycation end products (AGEs) at the levels that corresponded to approx. 25-30 years of the natural in vivo glycation. Cortical and cancellous bones from human tibias were glycated in vitro using either glucose (glucosylation) or ribose (ribosylation). Both glucosylation and ribosylation led to the formation of higher levels of AGEs and pentosidine (PEN) in cancellous than cortical bone dissected from all tested donors (young, middle-age and elderly men and women). More efficient glycation of bone matrix proteins in cancellous bone most likely depended on the higher porosity of this tissue, which facilitated better accessibility of the sugars to the matrix proteins. Notably, glycation of cortical bone from older donors led to much higher AGEs levels as compared to young donors. Such efficient in vitro glycation of older cortical bone could result from aging-related increase in porosity caused by the loss of mineral content. In addition, more pronounced glycation in vivo would be driven by elevated oxidation processes. Interestingly, the levels of PEN formation differed pronouncedly between glucosylation and ribosylation. Ribosylation generated very high levels of PEN (approx. 6- vs. 2.5-fold higher PEN level than in glucosylated samples). Kinetic studies of AGEs and PEN formation in human cortical and cancellous bone matrix confirmed higher accumulation of fluorescent crosslinks for ribosylation. Our results suggest that in vitro glycation of bone using glucose leads to the formation of lower levels of AGEs including PEN, whereas ribosylation appears to support a pathway toward PEN formation. Our studies may help to understand differences in the progression of bone pathologies related to protein glycation by different sugars, and raise awareness for excessive sugar supplementation in food and

  16. Glycoxidation of biological macromolecules: a critical approach to halt the menace of glycation.

    Science.gov (United States)

    Ahmad, Saheem; Khan, M Salman; Akhter, Firoz; Khan, Mohd Sajid; Khan, Amir; Ashraf, J M; Pandey, Ramendra Pati; Shahab, Uzma

    2014-11-01

    Glycation is the result of covalent bonding of a free amino group of biological macromolecules with a reducing sugar, which results in the formation of a Schiff base that undergoes rearrangement, dehydration and cyclization to form a more stable Amadori product. The final products of nonenzymatic glycation of biomacromolecules like DNA, proteins and lipids are known as advanced glycation end products (AGEs). AGEs may be generated rapidly or over long times stimulated by distinct triggering mechanisms, thereby accounting for their roles in multiple settings and disease states. Both Schiff base and Amadori glycation products generate free radicals resulting in decline of antioxidant defense mechanisms and can damage cellular organelles and enzymes. This critical review primarily focuses on the mechanistic insight of glycation and the most probable route for the formation of glycation products and their therapeutic interventions. Furthermore, the prevention of glycation reaction using therapeutic drugs such as metformin, pyridoxamine and aminoguanidine (AG) are discussed with special emphasis on the novel concept of the bioconjugation of these drugs like, AG with gold nanoparticles (GNPs). At or above 10 mM concentration, AG is found to be toxic and therefore has serious health concerns, and the study warrants doing this novel bioconjugation of AG with GNPs. This approach might increase the efficacy of the AG at a reduced concentration with low or no toxicity. Using the concept of synthesis of GNPs with abovementioned drugs, it is assumed that toxicity of various drugs which are used at high doses can be minimized more effectively.

  17. ADP-ribose in glycation and glycoxidation reactions.

    Science.gov (United States)

    Jacobson, E L; Cervantes-Laurean, D; Jacobson, M K

    1997-01-01

    Glycation is initiated by reaction of a reducing sugar with a protein amino group to generate a Schiff base adduct. Following an Amadori rearrangement to form a ketoamine adduct, a complex chemistry involving oxidation often leads to protein glycoxidation products referred to as advanced glycosylation end products (AGE). The AGE include protein carboxymethyllysine (CML) residues and a heterogeneous group of complex modifications characterized by high fluorescence and protein-protein cross links. The sugar sources for the glycoxidation of intracellular proteins are not well defined but pentoses have been implicated because they are efficient precursors for the formation of the fluorescent AGE, pentosidine. ADP-ribose, generated from NAD by ADP-ribose transfer reactions, is a likely intracellular source of a reducing pentose moiety. Incubation of ADP-ribose with histones results in the formation of ketoamine glycation conjugates and also leads to the rapid formation of protein CML residues, histone H1 dimers, and highly fluorescent products with properties similar to the AGE. ADP-ribose is much more efficient than other possible pentose donors for glycation and glycoxidation of protein amino groups. Recently developed methods that differentiate nonenzymic modifications of proteins by ADP-ribose from enzymic modifications now allow investigations to establish whether some protein modifications by monomers of ADP-ribose in vivo represent glycation and glycoxidation.

  18. 二甲双胍减轻糖基化终末产物对成骨细胞功能损害的观察%Metformin ameliorating the deleterious effects of advanced glycation end products on osteoblastic cells

    Institute of Scientific and Technical Information of China (English)

    甄东户; 汤旭磊; 成建国; 韩婕; 刘丽娟; 傅松波

    2012-01-01

    Objective To explore the effect of metformin on proliferation, differentiation and mineralization in the advanced glycation end products(AGEs)-induced rat cranium osteoblasts. Methods Rat cranium osteoblasts were isolated and cultured. The proliferation of osteoblasts was assayed by MTT method, the activity of alkaline phosphatase(ALP) was measured by biochemical method, the number of mineralized nodules was assessed by Alizarin red S staining, and the calcium deposition in the mineralized nodules was detected by hydrochloric acid decalcification method. Results With 500 fig/ml AGEs, the cellular proliferation, ALP activity, number of mineralized nodules, and calcium deposition were reduced significantly. Metformine (100-500 μmol/L) increased the cellular proliferation and ALP activity, and promoted the formation of mineralized nodules and calcium deposition in both control and AGEs groups. Conclusion AGEs inhibit the proliferation, differentiation and mineralization of the primary osteoblasts. Metformine strengthens the osteogenesis of osteoblasts and relieves the deleterious effect of AGEs on osteoblasts.%目的 观察二甲双胍对晚期糖基化终末产物(AGEs)诱导的大鼠颅骨成骨细胞增殖、分化、矿化的影响.方法 分离培养大鼠颅骨成骨细胞,四氮唑蓝(MTT)比色分析法测定细胞增殖,生化法测定碱性磷酸酶(ALP)活性、茜素红S钙染法检测矿化结节形成,盐酸脱钙法检测矿化结节中钙含量.结果 500μg/ml AGEs抑制成骨细胞增殖、ALP活性、钙化结节形成、钙沉积;给予二甲双胍(100~500 μmol/L)可不同程度上提高成骨细胞数量和ALP活性,促进矿化结节形成及钙沉积,减轻AGEs对成骨细胞增殖、ALP活性、钙化结节形成及钙沉积的抑制.结论 AGEs对原代成骨细胞增殖、分化与矿化产生抑制作用,二甲双胍提高成骨细胞的成骨能力,减轻AGEs对成骨细胞功能的损害.

  19. Pinocembrin protects against β-amyloid-induced toxicity in neurons through inhibiting receptor for advanced glycation end products (RAGE-independent signaling pathways and regulating mitochondrion-mediated apoptosis

    Directory of Open Access Journals (Sweden)

    Liu Rui

    2012-09-01

    Full Text Available Abstract Background It is known that amyloid-β peptide (Aβ plays a pivotal role in the pathogenesis of Alzheimer's disease (AD. Interaction between Aβ and the receptor for advanced glycation end products (RAGE has been implicated in neuronal degeneration associated with this disease. Pinocembrin, a flavonoid abundant in propolis, has been reported to possess numerous biological activities beneficial to health. Our previous studies have demonstrated that pinocembrin has neuroprotective effects on ischemic and vascular dementia in animal models. It has been approved by the State Food and Drug Administration of China for clinical use in stroke patients. Against this background, we investigated the effects of pinocembrin on cognitive function and neuronal protection against Aβ-induced toxicity and explored its potential mechanism. Methods Mice received an intracerebroventricular fusion of Aβ25-35. Pinocembrin was administrated orally at 20 mg/kg/day and 40 mg/kg/day for 8 days. Behavioral performance, cerebral cortex neuropil ultrastructure, neuronal degeneration and RAGE expression were assessed. Further, a RAGE-overexpressing cell model and an AD cell model were used for investigating the mechanisms of pinocembrin. The mechanisms underlying the efficacy of pinocembrin were conducted on target action, mitochondrial function and potential signal transduction using fluorescence-based multiparametric technologies on a high-content analysis platform. Results Our results showed that oral administration of pinocembrin improved cognitive function, preserved the ultrastructural neuropil and decreased neurodegeneration of the cerebral cortex in Aβ25-35-treated mice. Pinocembrin did not have a significant effect on inhibiting Aβ1-42 production and scavenging intracellular reactive oxygen species (ROS. However, pinocembrin significantly inhibited the upregulation of RAGE transcripts and protein expression both in vivo and in vitro, and also markedly

  20. Glycation in Parkinson's disease and Alzheimer's disease.

    Science.gov (United States)

    Vicente Miranda, Hugo; El-Agnaf, Omar M A; Outeiro, Tiago Fleming

    2016-06-01

    Glycation is a spontaneous age-dependent posttranslational modification that can impact the structure and function of several proteins. Interestingly, glycation can be detected at the periphery of Lewy bodies in the brain in Parkinson's disease. Moreover, α-synuclein can be glycated, at least under experimental conditions. In Alzheimer's disease, glycation of amyloid β peptide exacerbates its toxicity and contributes to neurodegeneration. Recent studies establish diabetes mellitus as a risk factor for several neurodegenerative disorders, including Parkinson's and Alzheimer's diseases. However, the mechanisms underlying this connection remain unclear. We hypothesize that hyperglycemia might play an important role in the development of these disorders, possibly by also inducing protein glycation and thereby dysfunction, aggregation, and deposition. Here, we explore protein glycation as a common player in Parkinson's and Alzheimer's diseases and propose it may constitute a novel target for the development of strategies for neuroprotective therapeutic interventions. © 2016 International Parkinson and Movement Disorder Society.

  1. 山茱萸环烯醚萜苷类成分对 AGEs诱导 HUVEC 损伤的保护作用%Protective effect of loganin and morroniside on HUVEC injury induced by advanced glycation end products

    Institute of Scientific and Technical Information of China (English)

    沈红胜; 许惠琴; 陆春红; 戴国英; 徐康; 吕兴; 陈玉萍; 吴云皓

    2016-01-01

    Aim To observe the protective mechanism of loganinand morroniside ( active components in Cornus officinalis) on HUVEC injury induced by advanced glycation end products ( AGEs ) .Methods HUVECs were cultured in vitro and divided into control group , model group ( AGEs group ) , loganin group , morroni-side group and aminoguanidine group ( set as positive control).After being incubated with loganin and mor-roniside( final concentrations were 100,10,1 μmol・L-1 ) for 1 h, HUVECs were stimulated by AGEs of 200 mg・ L-1 for 24 h.Then, the cell viability was measured by using MTT method .The supernatant was extracted and the levels of NO ,ET-1,MCP-1,VCAM-1 were measured by the corresponding kits .Receptors of advanced glycation end products ( RAGE ) and NF-κB in HUVEC were detected by Western blot .Results Loganin and morroniside could inhibit HUVEC injury induced by AGEs .In model group ,the contents of ET-1,MCP-1,VCAM-1 increased(P<0.01),the content of NO decreased ( P <0.01 ) and the expression of RAGE and NF-κB increased(P<0.01); however,lo-ganin and morronside could reduce the ET-1,MCP-1, VCAM-1contents,increase the NO content and down-regulate the expression of RAGE and NF-κB to differ-ent extents .Conclusion Loganin and morroniside could ameliorate HUVEC injury , and its mechanism may be related to inhibit inflammation , the improve-ment of endothelial cell function , and the decrease of the expression of RAGE .%目的:探讨山茱萸环烯醚萜苷类特征成分马钱苷、莫诺苷对糖基化终末产物( AGEs )诱导人脐静脉内皮细胞( HUVEC)损伤的保护作用。方法体外培养HUVEC,用马钱苷、莫诺苷(终浓度分别为100、10、1μmol・ L-1)预孵1 h后,再加入AGEs(200 mg・ L-1)刺激,并设氨基胍为阳性对照,孵育24 h后,采用MTT法检测马钱苷、莫诺苷对HUVEC增殖率的影响;采用试剂盒检测细胞上清液中一氧化氮(NO)、内皮素(ET-1)

  2. Effect of advanced glycation end products on renin-angiotensin system in podocytes%晚期糖基化终产物对足细胞内肾素-血管紧张素系统的影响

    Institute of Scientific and Technical Information of China (English)

    成彩联; 郑振达; 石成钢; 叶增纯; 刘迅; 娄探奇

    2013-01-01

    Objective To investigate the effect and mechanism of advanced glycation end products (AGEs) on the components of renin-angiotensin system (RAS) in the podocytes.Methods Immortalized mouse podocytes were exposed to various concentrations of AGEs for 24 h.The expression levels of renin,angiotensinogen (AGT) and angiotensin Ⅱ type 1 and 2 receptors (AT1R and AT2R),the level of angiotensin Ⅱ (Ang Ⅱ),and the activity of angiotensin-converting enzyme (ACE) were assayed.The levels of Akt and phosphorylated Akt were examined by Western blotting.Cell adhesion was measured in the podocytes pretreated with phosphoinositide 3-kinase (PI3-K) inhibitor LY294002,losartan,captopril and chymostatin,respectively.Results Treatment with AGEs resulted in significant increase in the expression of AGT and AT1R.Moreover,ACE activity and Ang Ⅱ level increased significantly.However,there was no significant change in renin and AT2R expression.AGEs increased the phosphorylation of Akt by 100%.When the podocytes were pretreated with LY294002 (10 μmol/L),the AGEs-induced increase in AGT and AT1R expression reduced remarkably.Likewise,ACE activity and Ang Ⅱ level decreased significantly,and the reduced podocyte adhesive capacity induced by AGEs was improved significantly.Conclusions AGEs activate the RAS via PI3-K/Akt-dependent pathway,and lead to a decrease in podocyte adhesion.%目的 观察晚期糖基化终产物(advanced glycation end products,AGEs)对足细胞内肾素-血管紧张素系统(renin-angiotensin system,RAS)的影响及作用机制.方法 不同浓度的AGEs干预小鼠足细胞24h,分别检测肾素(renin)、血管紧张素原(renin-angiotensin system,AGT)、血管紧张素Ⅱ1型、2型受体(AT1R、AT2R)的表达,血管紧张素转换酶(angiotensin-converting enzyme,ACE)的活性和血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)的浓度,观察蛋白激酶B(Akt)的磷酸化,然后分别加入磷酸肌醇3激酶抑制剂LY294002、Iosartan、captopril和chymastatin,

  3. Inhibition of glucose- and fructose-mediated protein glycation by infusions and ethanolic extracts of ten culinary herbs and spices

    Institute of Scientific and Technical Information of China (English)

    Jugjeet Singh Ramkissoon; Mohamad Fawzi Mahomoodally; Anwar Hussein Subratty; Nessar Ahmed

    2016-01-01

    Objective: To investigate the inhibitory activity of ten culinary herbs and spices namely on glucose-mediated glycation (GMG) and fructose-mediated glycation (FMG) of bovine serum albumin. Methods: Fluorescence was used as an index of albumin glycation using glucose and fructose as substrates in the presence of infusions and ethanolic extracts of ten culinary herbs and spices. Antioxidant activity of the extracts was evaluated using reducing power, metal ion chelating and superoxide radical scavenging assays. Phytochemicals profile was analysed using 13 standard methods. Results: FMG was found to be significantly higher than GMG (95 and 84 AU, respectively; P 0.05) was found in the percentage glycation inhibitory activity of infusions compared to ethanolic extracts. The mean percentage inhibitory activity of the extracts for GMG (45.9%) and for FMG (45.1%) was not significantly different (P > 0.05). Qualitative phytochemical analysis showed the presence of alkaloids, fla-vonoids, tannins, terpenoids, anthraquinones, steroids, reducing sugars, proteins, phenols, saponins, phlobatannins, and cardiac glycosides. Conclusions: The higher rate of fluorescence generation by fructation suggests that glycation by fructose deserves much attention as a glycating agent. Data herein showed that the extracts inhibited GMG and FMG. Thus, these edible plants could be a natural source of antioxidants and anti-glycation agent for preventing advanced glycation end-products-mediated complications.

  4. Review: Glycation of human serum albumin.

    Science.gov (United States)

    Anguizola, Jeanethe; Matsuda, Ryan; Barnaby, Omar S; Hoy, K S; Wa, Chunling; DeBolt, Erin; Koke, Michelle; Hage, David S

    2013-10-21

    Glycation involves the non-enzymatic addition of reducing sugars and/or their reactive degradation products to amine groups on proteins. This process is promoted by the presence of elevated blood glucose concentrations in diabetes and occurs with various proteins that include human serum albumin (HSA). This review examines work that has been conducted in the study and analysis of glycated HSA. The general structure and properties of HSA are discussed, along with the reactions that can lead to modification of this protein during glycation. The use of glycated HSA as a short-to-intermediate term marker for glycemic control in diabetes is examined, and approaches that have been utilized for measuring glycated HSA are summarized. Structural studies of glycated HSA are reviewed, as acquired for both in vivo and in vitro glycated HSA, along with data that have been obtained on the rate and thermodynamics of HSA glycation. In addition, this review considers various studies that have investigated the effects of glycation on the binding of HSA with drugs, fatty acids and other solutes and the potential clinical significance of these effects.

  5. The Expression of Receptor Advanced Glycation End-products and Type IV Collagen in Ovary Tissues of Women with Polycystic Ovary Syndrome%RAGE与Col4在多囊卵巢综合征患者中的表达

    Institute of Scientific and Technical Information of China (English)

    涂灵; 易迎春

    2009-01-01

    目的 探讨糖化终末产物受体(RAGE)与IV胶原(Col4)在多囊卵巢综合征患者中的表达.方法 采用逆转录聚合酶链式反应(RT-PCR)方法对20例正常卵巢组织和40例多囊卵巢综合征[其中胰岛素抵抗组(IR)22例,非胰岛素抵抗组(NIR)18例]的卵巢组织进行RAGE和IV胶原a1(Col4A1)表达情况的半定量检测.结果 RAGE在PCOS患者IR组和NIR组中表达均高于对照组(P<0.001,P<0.05),在PCOS患者IR组的表达高于NIR组(P<0.05);Col4A1在PCOS患者IR组和NIR组中表达均高于对照组(P<0.001,P<0.05),在PCOS患者IR组的表达高于NIR组(P<0.05).结论 RAGE与Col4在多囊卵巢综合征患者中的高表达可能与其发病机制存在一定的关系.

  6. Effects of advanced glycation end-products on the expression of GLP-1 receptor and apopotis in cultured cardiomyocytes%糖基化终产物对心肌细胞GLP-1受体表达及凋亡影响的研究

    Institute of Scientific and Technical Information of China (English)

    胡波; 李德才

    2013-01-01

    目的 探讨糖基化终产物(AGEs)对乳鼠心肌细胞胰高血糖素样肽1受体(GLP-1R)、caspase-3表达及凋亡的影响.方法 原代培养乳鼠心肌细胞,以不同浓度葡萄糖孵育的糖化清蛋白(AGE-BSA)干预24h和同一浓度葡萄糖孵育的AGE-BSA干预24~72h,检测其对心肌细胞GLP-1RmRNA、活化的caspase-3表达及凋亡的影响.结果 AGE-BSA 可抑制心肌细胞GLP-1RmRNA表达,并诱导细胞caspase-3表达,凋亡增加.各AGE-BSA 组间及与对照组比较差异有统计学意义(P<0.05).结论 AGE-BSA 能抑制心肌细胞GLP-1RmRNA表达,并诱导细胞caspase-3表达,增加细胞凋亡,提示糖基化终产物在糖尿病心肌病的发生中可能具有重要的作用.

  7. Advanced glycation end-products decreases THP-1 macrophages expression of peroxisome proliferator activated receptor-γ%糖基化终产物抑制THP-1巨噬细胞过氧化物酶体增殖物激活受体γ的表达

    Institute of Scientific and Technical Information of China (English)

    杨启红; 徐强; 张红; 司良毅

    2008-01-01

    目的:观察糖基化终产物(AGEs)对THP-1巨噬细胞过氧化物酶体增殖物激活受体γ(PPARγ)表达的影响,探讨AGEs在糖尿病动脉粥样硬化中可能的作用.方法:用佛波酯(PMA)诱导THP-1单核细胞72h使其分化为巨噬细胞,并将糖基化-牛血清白蛋白(AGE-BSA)与巨噬细胞共同孵育,运用RT-PCR和免疫细胞化学法分别检测巨噬细胞PPARγ mRNA和蛋白的表达水平.结果:PMA诱导72h后,THP-1细胞停止增殖,由单核细胞分化成为巨噬细胞.50、100、200和400μg/mlAGE-BSA处理24h后,巨噬细胞PPARγ mRNA相对表达量分别是1.235±0.044、0.752±0.055、0.494±0.026、0.277±0.025;PPARγ蛋白的平均积分光密度值分别为36.460±0.625、24.561±0.636、19.326±0.803、12.715±0.752,二者较100μg/ml牛血清白蛋白(BSA)组均明显降低(P<0.05).200μg/ml AGE-BSA作用12、24、36和48h后,巨噬细胞PPARγ mRNA相对表达量分别是1.564±0.060、1.260±0.043、0.467±0.033、0.360±0.012;PPARγ蛋白的平均积分光密度值分别为32.502±0.739、22.234±0.835、16.568±0.683、11.537±0.547,二者较0h组也明显降低(P<0.05 o结论:AGEs可下调THP-1巨噬细胞PPARγmRNA和蛋白的表达水平,且呈浓度和时间依赖性.

  8. Advances in Toxicology of Nε-(carboxymethyl)-lysine (CML)%羧甲基赖氨酸的毒理学研究进展

    Institute of Scientific and Technical Information of China (English)

    张振华; 孙建霞; 白卫滨; 欧仕益; 邱瑞霞

    2013-01-01

    晚期糖基化终末产物(Advanced Glycation End-products,AGEs)是蛋白质、脂质或核酸等大分子物质的非酶糖基化产物。其中,羧甲基赖氨酸(CML)是 AGEs的主要结构成分之一,在体内广泛分布,其在生物体内及食品加工和加热过程中均有生成。研究表明,羧甲基赖氨酸(CML)作为 AGEs的主要抗原表位,在糖尿病及多种并发症以及衰老的发生发展过程中起着重要作用。该研究对羧甲基赖氨酸(CML)的主要来源、毒理危害以及控制等进展进行综述。%Advanced glycation end-products (AGEs) are products of non-enzymatic glycation of proteins, lipids or nucleic acids and other macromolecules. To be spe-cific, Nε-(carboxymethyl)-lysine (CML) is one of the most important components of AGEs, which is wildly distributed in the body and can be formed in vivo or in food processing and heating processes. Previous studies have shown that CML is a ma-jor immunological epitope in AGEs and plays an important role in diabetes and its complications, as wel as in the development and progression of aging. This review summarized recent advances in major source, toxicological hazard and control mea-sures of CML.

  9. 糖基化终产物对成骨细胞I型胶原积聚的影响%The effect of advanced glycation end products on the accumulation of type I collagen

    Institute of Scientific and Technical Information of China (English)

    蔡若男; 金晖; 张丽娟

    2011-01-01

    目的 探讨糖基化终产物(AGEs)对成骨细胞与破骨前体细胞共培养体系中I型胶原合成与降解的影响.方法 在成骨细胞与破骨前体细胞共培养体系中分别加入不同浓度的糖基化终产物(50、100、200、400mg/L)干预24h,以无血清培养基和相应浓度的牛血清白蛋白为对照.用免疫印迹的方法检测I型胶原蛋白水平的表达,酶联免疫吸附法检测上清中I型胶原的含量,用明胶酶谱法检测上清中MMP-2、MMP-9的活性.结果 AGEs干预组的I型胶原蛋白水平和上清中含量与对照组比较有显著差异,I型胶原蛋白水平随浓度增加而增加(P<0.05),上清中I型胶原含量随AGEs浓度增加而减少(P<0.05).糖基化终产物干预后,上清中MMP-2、MMP-9的活性随着AGEs浓度的增加而增加(P<0.05).结论 AGEs可能通过打破I型胶原合成与降解之间的平衡,使其降解多于合成,I型胶原总量减少,从而参与骨质疏松的发病,使骨骼脆性增加.%Objective To explore the effect of advanced glycation end products ( AGEs) on the synthesis and degradation of type I collagen in a co-cultured system of osteoblast and osteoclast precursors. Methods The AGEs of 50, 100, 200, and 400 mg/L different concentrations were respectively added into the co-cultured system of osteoblast and osteoclast precursors for 24 hours. The serum free medium and bovine serum albumin (BSA) were considered as negative control. The expression of type I collagen protein was measured using Western blotting method. The concentration of type I collagen in the supernatant was measured using enzyme linked immunosorbent assay (ELISA). The activity of MMP-9 and MMP-2 were measured using gelatin enzymogram. Results The expression of type I collagen protein and concentration of type I collagen in the supernatant in AGEs group were significantly different with those of DMEM and BSA groups. The level of type I collagen protein expression increased with the

  10. 糖基化终末产物对人外周血内皮祖细胞生物学特性的影响%Effects of advanced glycation end products on endothelial progenitor cells in the blood

    Institute of Scientific and Technical Information of China (English)

    闫醒军; 施森; 姜隽; 何延政; 边忠平; 刘勇; 黄启荣; 崔驰; 周秀娟; 杨辉; 钟武; 曾宏

    2010-01-01

    Objective In addition to be involved in the angiogenesis, endothelial progenitor cells (EPCs) have roles in endothelium repairing, wound healing, and for protecting blood vessels from restenosis, Advanced glycation end products (AGEs) facilitate the development and progression of atherosclerosis, diabetes associated vascular complications and uremia through various mechanisms such as damaging the endothelium, promoting leukocyte adhension, increasing the aggregation of platelets, and stimulating the proliferation of vascular smooth muscles. This study was designed to explore whether AGEs have effects on biological characteristics of EPCs in cultured human peripheral blood cells. Methods Total mononuclear cells (MNCs), isolated from human peripheral blood by density gradient centrifugatian and adherence cells filtration, were incuba-ted in fibronectin-coated culture dishes. Endothelial cells were identified by means of the adsorption of ulex eurepaeus-aggluti-nin- Ⅰ (UEA- Ⅰ) labelled with fluorescein isothiacyanate (FITC) and Dil-acLDL internalization. Four days later,various con-centrations of AGEs were added to the adherent cells and remained for48 hours. MTT assay and Boyden chamber were used for observing the proliferation and migration of EPCs. Human fibronectin was used to examine the adhesion ability of EPCs. Apop-tosis was induced in the EPCs with formaldehyde and Dnase Ⅰ as a positive control group. Annexin V-FITC/PI and TUNEL method of flow cytometry were used for evaluating the effects of AGEs on the rate of apeptosis in the EPCs. Results AGEs at high concentration decreased the number of EPCs independently (P < 0.01) ; reduced the proliferation (P < 0.01), migration (P<0.001) and adhesive capacity (P<0.05) of EPCs significantly,as well as increasing the apoptasis rate of EPCs in the early stage (P < 0.001). Conclusion AGEs may have adverse effects on EPCs from cultured human peripheral MNCs, such as decreasing their numbers and impairing their

  11. 糖基化终末产物抑制骨髓间充质干细胞功能的机制%Mechanism of advanced glycation end products inhibiting function of bone mesenchymal stem cells

    Institute of Scientific and Technical Information of China (English)

    孟宪丽; 孟华; 陈岩

    2016-01-01

    Objective To explore the mechanism of advanced glycation end products (AGEs) attenuating the proliferation and migration in mesenchymal stem cells (MSCs).Methods The MSCs were isolated from male Sprague Dawley rats,and identified by flow cytometry (positive:CD29 and CD90;negative:CD34 and CD45).MSCs were stimulated by AGEs-bovine serum albumin (BSA) with different doses (0,25,50,100 and 200 mg/L) and time (6,12 and 24 h).The proliferation of cells was examined by methyl thiazol tetrazolium (MTT) assay.Wound-healing assay was used to assess the migration potential of cells treated with AGEs-BSA.Intracellular formation of reactive oxygen species (ROS) was evaluated using a fluorescent probe.Results The relative metabolic activity was significantly reduced by 81.22%,80.53% and 51.50% with AGEs-BSA (200 mg/L) at 6,12,and 24 h,respectively.The proliferation potential of MSCs was impacted by AGEs-BSA in a dose-and time-dependent manner.AGEs-BSA (200 mg/L for 24 h) obviously inhibited migration of MSCs [(0.012 ±0.006) μm/min vs.(0.022-±0.002) μm/min,P <0.01].At the same time,AGEs-BSA significantly induced the intracellular ROS accumulation.Conclusion AGEs-BSA induced ROS formation via receptor to inhibit proliferation and migration.%目的 探讨糖基化终末产物(AGEs)对间充质干细胞(MSCs)增殖和迁移能力的影响及其机制.方法 体外培养SD大鼠MSCs,流式细胞术鉴定阳性指标(CD29和CD90)和阴性指标(CD34和CD45).噻唑蓝(MTT)比色法检测不同剂量(0、25、50、100、200 mg/L) AGEs-牛血清白蛋白(BSA)在刺激不同时间(6、12、24h)后MSCs增殖变化.采用Wound-healing划痕实验检测不同剂量(0、25、50、100、200 mg/L) AGEs-BSA刺激骨髓间充质干细胞24h后的迁移能力.荧光染色拍照测定AGEs-BSA(200 mg/L)刺激12、24h后细胞内活性氧(ROS)累积情况.结果 200 mg/L AGEs-BSA刺激6、12、24 h MSCs增殖能力显著下降,分别为81.22%、80.53%、51.50%,AGEs-BSA抑制细胞

  12. Apoptosis of rat periodontal ligament fibroblasts induced by advanced glycation end products and its receptor%糖基化终产物及其受体对牙周膜成纤维细胞凋亡影响的实验研究

    Institute of Scientific and Technical Information of China (English)

    邓天政; 吕晶; 冯岩; 李冬霞; 刘冰; 逄键梁; 臧晓霞; 柯杰

    2012-01-01

    目的 观察糖基化终产物(advanced glycation end products,AGE)促进糖基化终产物受体(receptor for advanced glycation end products,RAGE)在大鼠牙周膜成纤维细胞(periodontal ligament fibroblasts,PDLF)中的表达情况,并研究RAGE在大鼠PDLF凋亡中的作用.方法 第3代大鼠PDLF在含有终浓度为200 mg/L的糖基化牛血清白蛋白(advanced glycation end products-bovine serum albumin,AGE-BSA)培养基内培养,根据孵育时间分为实验组A1、A2、A3、A4组;相同条件下PDLF于终浓度200 mg/L的BSA孵育,按与A1 ~ A4组相同的孵育时间分为实验组B1、B2、B3、B4;在无AGE-BSA、BSA的培养基内培养第3代PDLF设为对照组C组.检测各组细胞活性、细胞凋亡情况、RAGE及细胞凋亡蛋白酶3 mRNA表达情况.结果 AGE干预的大鼠PDLF在细胞形态学及细胞活性检测方面均发生改变.相同时间点A、B各组细胞活性组间比较差异具有统计学意义(P<0.01),A1、A2、A3、A4 4组细胞活性的组间差异无统计学意义(F=2.353,P=0.088),B1、B2、B3、B44组的组间差异亦无统计学意义(F=0.468,P=0.706).经流式细胞术检测,实验组A1、A2、A3、A4组细胞凋亡比例依次明显增高,与C组比较差异具有统计学意义(P<0.01).受AGE干预的细胞可以表达RAGE且细胞凋亡蛋白酶3表达阳性.结论 AGE可以刺激大鼠PDLF表达RAGE,促进细胞凋亡.%Objective To detect receptor for advanced glycation end products expression level produced in rat periodontal ligament fibroblasts cultured in vitro, and to evaluate the mechanism of apoptosis in this progress. Methods Rat periodontal ligament fibroblasts induced by advanced glycation end products-bovine serum albumin (AGE-BSA) and bovine serum albumin (BSA) , were collected and were devided into 8 groups according to the intervention time in vitro, while no interventions is control group. The cell viability was evaluated with 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H

  13. Bioactive ginger constituents alleviate protein glycation by trapping methylglyoxal.

    Science.gov (United States)

    Zhu, Yingdong; Zhao, Yantao; Wang, Pei; Ahmedna, Mohamed; Sang, Shengmin

    2015-09-21

    Considerable evidence suggests that long-term pathological diabetes is a result of the accumulation of tissue macromolecules that have been progressively modified by nonenzymatic glycation of protein. Methylglyoxal (MGO) is a highly reactive endogenous dicarbonyl metabolite derived from multiple sources such as glucose and lipids and is thought to contribute greatly to protein glycation and the formation of advanced glycation end products (AGEs). In this study, we demonstrated for the first time that both [6]-shogaol (6S) and [6]-gingerol (6G), the major active components in ginger, markedly trapped MGO in vitro and consequently formed mono-MGO adducts, 6S-MGO and 6G-MGO, which were purified from the respective chemical reaction and characterized as novel compounds by NMR experiments and LC-MS/MS approaches. We revealed that the α-carbon of the carbonyl group in the side chain of 6S or 6G is the major active site for trapping MGO. We also demonstrated that 6S and 6G could effectively inhibit the formation of MGO-induced AGEs via trapping MGO in a time-dependent manner in the human serum albumin (HSA)-MGO system. Mono-MGO adducts, 6S-MGO and 6G-MGO, were determined to be the major conjugates in 6S- and 6G-treated HSA-MGO assays, respectively, using LC-ESI-MS techniques. These findings showed the potential effects of 6S and 6G on the prevention of protein glycation, suggesting regular consumption of ginger root extract may attenuate the progression of MGO-associated diabetic complications in patients.

  14. Inhibitory effect of Piper betle Linn. leaf extract on protein glycation--quantification and characterization of the antiglycation components.

    Science.gov (United States)

    Bhattacherjee, Abhishek; Chakraborti, Abhay Sankar

    2013-12-01

    Piper betle Linn. is a Pan-Asiatic plant having several beneficial properties. Protein glycation and advanced glycation end products (AGEs) formation are associated with different pathophysiological conditions, including diabetes mellitus. Our study aims to find the effect of methanolic extract of P. betle leaves on in vitro protein glycation in bovine serum albumin (BSA)-glucose model. The extract inhibits glucose-induced glycation, thiol group modification and carbonyl formation in BSA in dose-dependent manner. It inhibits different stages of protein glycation, as demonstrated by using glycation models: hemoglobin-delta-gluconolactone (for early stage, Amadori product formation), BSA-methylglyoxal (for middle stage, formation of oxidative cleavage products) and BSA-glucose (for last stage, formation of AGEs) systems. Several phenolic compounds are isolated from the extract. Considering their relative amounts present in the extract, rutin appears to be the most active antiglycating agent. The extract of P. betle leaf may thus have beneficial effect in preventing protein glycation and associated complications in pathological conditions.

  15. 2型糖尿病大鼠骨折愈合障碍与体内晚期糖基化终末产物的变化%Impaired fracture healing and change of advanced glycation end products in vivo in type 2 diabetes rats

    Institute of Scientific and Technical Information of China (English)

    刘振东; 刘亚江; 高敏伟; 黄祖发; 廖小军; 石磊

    2014-01-01

    背景:近年来,晚期糖基化终末产物在骨组织领域的作用日益受到重视,而糖代谢紊乱是引起晚期糖基化终末产物增加的主要原因之一。  目的:观察2型糖尿病大鼠体内晚期糖基化终末产物表达的变化,并探讨其与糖尿病骨折愈合障碍的关系。方法:30只SD大鼠随机均分为2组,实验组制备2型糖尿病模型,对照组正常饲养。糖尿病模型制备成功后,所有大鼠建立左胫骨骨折牵引成骨模型,胫骨延长0.3 mm/d,持续14 d。  结果与结论:牵引结束后,X 射线摄片显示实验组糖尿病模型大鼠骨折断端之间牵引骨痂形成较对照组明显减少;骨痂组织学检查表现为微骨柱排列紊乱,初始基质前沿浅染。ELISA 法检测实验组血清和双侧骨痂组织中晚期糖基化终末产物水平较对照组明显升高(P OBJECTIVE:To observe the change of advanced glycation end products expressed in type 2 diabetes rats, and to investigate the relationship between impaired fracture healing and change of advanced glycation end products expression in vivo. METHODS:Thirty Sprague-Dawley rats were randomly and equal y divided into two groups:control group (normal feeding) and experimental group (high fat and sucrosum diet feeding to establish type 2 diabetes model). After diabetes models were established, the model of distraction osteogenesis in the left tibiae of al the rats was produced. Distraction was given 0.3 mm per day and continued for 14 days. RESULTS AND CONCLUSION:After the traction was complete, cal us formation in distraction gap was obviously reduced in experimental group compared with control group by X-ray examination. The array of microcolumn formation was disordered and the area of primary matrix front was catachromasis by histology examination. The enzyme-linked immunosorbent assay results showed that, the level of advanced glycation end products was obviously elevated (P<0

  16. Comprehensive Identification of Glycated Peptides and Their Glycation Motifs in Plasma and Erythrocytes of Control and Diabetic Subjects

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qibin; Monroe, Matthew E.; Schepmoes, Athena A.; Clauss, Therese RW; Gritsenko, Marina A.; Meng, Da; Petyuk, Vladislav A.; Smith, Richard D.; Metz, Thomas O.

    2011-07-01

    Non-enzymatic glycation of proteins is implicated in diabetes mellitus and its related complications. In this report, we extend our previous development and refinement of proteomics-based methods for the analysis of non-enzymatically glycated proteins to comprehensively identify glycated proteins in normal and diabetic human plasma and erythrocytes. Using immunodepletion, enrichment, and fractionation strategies, we identified 7749 unique glycated peptides, corresponding to 3742 unique glycated proteins. Semi-quantitative comparisons revealed a number of proteins with glycation levels significantly increased in diabetes relative to control samples and that erythrocyte proteins are more extensively glycated than plasma proteins. A glycation motif analysis revealed amino acids that are favored more than others in the protein primary structures in the vicinity of the glycation sites in both sample types. The glycated peptides and corresponding proteins reported here provide a foundation for the potential identification of novel markers for diabetes, glycemia, or diabetic complications.

  17. Effects of sodium ferulate on the mRNA of receptor for advanced glycation end products in kidneys of diabetic rats%阿魏酸钠对糖尿病大鼠肾脏糖基化终产物受体mRNA表达的影响

    Institute of Scientific and Technical Information of China (English)

    赵同峰; 邓华聪; 李全民

    2004-01-01

    目的探讨阿魏酸钠(sodium ferulate,SF)对糖尿病(diabetes mellitus,DM)大鼠肾脏皮质糖基化终产物受体(receptor for advanced glycation end products,RAGE)mRNA表达的影响.方法对链脲佐菌素(streptozotocin,STZ)诱导的DM大鼠灌胃给予SF110 mg·kg-1·d-1),治疗8周,测定各组大鼠肾重/体重、血尿素氮(blood urea nitrogen,BUN)、血肌酐(serum creatinine,Scr)、24h尿蛋白定量,并用RT-PCR方法检测肾脏皮质RAGEmRNA的表达,观察肾脏病理改变.结果DM组大鼠肾重/体重,BUN,Scr,24h尿蛋白定量,肾皮质RAGEmRNA的表达显著高于正常对照组;SF组肾重/体重,BUN,24h尿蛋白定量,肾皮质RAGE mRNA的表达显著低于DM组;DM组大鼠肾脏病理显著异常,SF可显著减轻其病理学改变.结论SF可通过抑制肾脏RAGE mRNA的表达,减轻糖基化终产物(advanced glycation end products,AGEs)-RAGE之间的相互作用对DM大鼠肾脏产生保护作用.

  18. Inhibition Effect and Mechanism of Cariporide on Neointimal Proliferation Induced by Advanced Glycation End Products%卡立泊来德对AGEs所致新内膜形成的抑制作用及相关机制

    Institute of Scientific and Technical Information of China (English)

    吴树金; 杨青山; 宋涛; 周寿红; 刘玉辉; 刘立英

    2013-01-01

    In order to investigate the inhibitory effect of cariporide,a specific Na+/H+ exchanger 1 (NHE1)blocker,on neointimal proliferation induced by AGEs in a carotid artery balloon injury model,the rats carotid artery was balloon injured.The exemplars were collected and stained by HE.The morphology changes were observed.The intima area,media area and the ratio of area between intima and media were calculated using image analysis system.In order to explore the precise mechanism,the experiments were done on the isolated rat vascular smooth muscle cells (VSMC).Cell proliferation was assessed by [3H] thymidine incorporation.RT-PCR and Real-time RT-PCR were used to assay the cyclooxygenase-2 (COX-2) matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinases-9 (MMP-9) expression; Westem blot was used to assay NF-κB protein and the degradation of the inhibitor Ⅰ-κBα The in vivo results shows that neointima hyperplasia is significantly suppressed treated with cariporide in balloon-injured rats compared with AGEs treatment lonely.The in vitro study shows that cariporide dose-dependently inhibited AGEs-induced upregulation of COX-2,MMP-2 and MMP-9 expression.We also found that cariporide blocked AGEs-induced activation of nuclear factor-κB (NF-κB)and pointed out that inhibition of NF-κB was achieved by inhibiting the degradation of the inhibitor Ⅰ-κBα.The results identified that NHE1 inhibitor cariporide inhibited AGEs-induced neointimal hyperplasia in rats balloon-injured model by suppressing the proliferation of VSMC and the upregulation of COX-2,MMP-2 and MMP-9 via inhibiting NF-κB activation in VSMC.These results indicated that NHE1 might be a considerable ingredient of the signal pathway in which AGEs played a key role in the processes of vascular damage.%为了观察Na+/H+交换蛋白1(NHE1)选择性抑制剂卡立泊来德(cariporide)对糖基化终末产物(advanced glycation end products,AGEs)所致大鼠颈动脉球囊损伤后新内膜形成的作

  19. Sri Lankan black tea (Camellia sinensis L.) inhibits the methylglyoxal mediated protein glycation and potentiates its reversing activity in vitro

    Institute of Scientific and Technical Information of China (English)

    Wanigasekara Daya Ratnasooriya

    2016-01-01

    Objective: To evaluate inhibitory activity of methylglyoxal (MGO) mediated protein glycation and ability to potentiate its reversing activity and range of antioxidant properties of Sri Lankan low grown orthodox orange pekoe grade black tea. Methods: Freeze dried black tea brew (BTB) was used as the sample in this study. Anti-glycation and glycation reversing activity was studied in bovine serum albumin (BSA)-MGO model. Antioxidant properties were studied using total polyphenolic content, total flavonoid content, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, 1,1-diphenyl-2-picrylhydrazine and ferric reducing antioxidant power in vitro antioxidant assays. Results: The results demonstrated significant (P Conclusions: The novel properties observed for Sri Lankan orange pekoe grade black tea indicate its usefulness as a supplementary beverage in managing MGO and advanced glycation end products related diseases and ailments.

  20. Anti-glycated and antiradical activities in vitro of polysaccharides from Ganoderma capense

    Directory of Open Access Journals (Sweden)

    Chunyan Yan

    2013-01-01

    Full Text Available Background : Ganoderma capense is a Ganoderma species and is widely used, especially in Asia, as a well-known medicinal mushroom for health-promoting effect and for treatment of chronic diseases, such as diabetes, aging, etc. G. capense is rich of polysaccharide. Objective: To isolate the polysaccharides from G. capense and evaluate their anti-glycated and antiradical activities in vitro. Materials and Methods : The dried powder of submerged fermentation culturing mycelium of G. capense was defatted, extracted with water/ alkaline water followed by ethanol precipitation and deproteinated. And four crude polysaccharides, named as GC50, GC70, GC90 and GCB, were obtained. For the first time, the in vitro anti-glycated activities of the four samples were studied by non-enzymatic glycation reaction. Then, the DPPH radical and hydroxyl radical assays were established to estimate the antiradical capacity of the four samples. Meanwhile the contents of polysaccharides were determined by phenol-sulphuric acid colorimetry. Results and Conclusion : Preliminary antiradical in vitro studies indicated that the four crude polysaccharides showed concentration-dependent scavenging abilities on DPPH and hydroxyl radicals. The evaluation of anti-glycation activity suggested that GC70 had good potential for inhibiting the formation of advanced glycation end products. Time- and dose-dependent effects were also observed for all GC70 samples.

  1. Fisetin lowers methylglyoxal dependent protein glycation and limits the complications of diabetes.

    Directory of Open Access Journals (Sweden)

    Pamela Maher

    Full Text Available The elevated glycation of macromolecules by the reactive dicarbonyl and α-oxoaldehyde methylglyoxal (MG has been associated with diabetes and its complications. We have identified a rare flavone, fisetin, which increases the level and activity of glyoxalase 1, the enzyme required for the removal of MG, as well as the synthesis of its essential co-factor, glutathione. It is shown that fisetin reduces two major complications of diabetes in Akita mice, a model of type 1 diabetes. Although fisetin had no effect on the elevation of blood sugar, it reduced kidney hypertrophy and albuminuria and maintained normal levels of locomotion in the open field test. This correlated with a reduction in proteins glycated by MG in the blood, kidney and brain of fisetin-treated animals along with an increase in glyoxalase 1 enzyme activity and an elevation in the expression of the rate-limiting enzyme for the synthesis of glutathione, a co-factor for glyoxalase 1. The expression of the receptor for advanced glycation end products (RAGE, serum amyloid A and serum C-reactive protein, markers of protein oxidation, glycation and inflammation, were also increased in diabetic Akita mice and reduced by fisetin. It is concluded that fisetin lowers the elevation of MG-protein glycation that is associated with diabetes and ameliorates multiple complications of the disease. Therefore, fisetin or a synthetic derivative may have potential therapeutic use for the treatment of diabetic complications.

  2. Plasma disappearance of glycated and non-glycated albumin in type 1 (insulin-dependent) diabetes mellitus

    DEFF Research Database (Denmark)

    Bent-Hansen, L; Feldt-Rasmussen, B; Kverneland, Arne;

    1993-01-01

    The fractional plasma escape rates of glycated and non-glycated albumin have earlier been measured in groups of Type 1 (insulin-dependent) diabetic patients and control subjects. The escape of non-glycated albumin was similar in control subjects and normoalbuminuric patients, but elevated...... in patients with micro or macroalbuminuria. In all groups the escape rate of glycated albumin was lower than that of non-glycated albumin. Glycation increases the anionic charge of albumin. To assay for charge-dependent alterations of transport a selectivity index (non-glycated albumin/glycated albumin...... transport ratio) was determined from the disappearance data. The index was high in control subjects (1.021 +/- 0.0057 (SEM)). This reflects a mean difference between the two escape rates of 2.1% per hour (for comparison the mean of the fractional escape rate of non-glycated albumin of the normal control...

  3. Role of early glycation Amadori products of lysine-rich proteins in the production of autoantibodies in diabetes type 2 patients.

    Science.gov (United States)

    Ansari, Nadeem Ahmad; Moinuddin; Mir, Abdul Rouf; Habib, Safia; Alam, Khursheed; Ali, Asif; Khan, Rizwan Hasan

    2014-11-01

    In diabetes, protein glycation mostly occurs at intrachain lysine residues resulting in the formation of early stage Amadori products which are finally converted to advance glycation end products (AGEs). Several studies have reported autoantibodies against AGEs in diabetes but not much data are found in respect of Amadori products. In this study, poly-L-lysine (PLL) was glycated with 50 mM glucose and the resultant Amadori products were estimated by fructosamine or nitroblue tetrazolium assay. We report high content of Amadori products in PLL upon glycation. Glycated PLL showed marked hyperchromicity in the UV spectrum, ellipticity changes in CD spectroscopy, and variations in ε-methylene protons shift in NMR. It was better recognized by autoantibodies in type 2 diabetics compared to the native PLL. Induced antibodies against glycated PLL were successfully used to probe early glycation in the IgG isolated from diabetes type 2 patients. Role of Amadori products of glycated proteins in the induction of autoantibodies in type 2 diabetes as well as in associated secondary complications has been discussed.

  4. Determination of membrane protein glycation in diabetic tissue

    OpenAIRE

    Zhang, Eric Y.; Swaan, Peter W.

    1999-01-01

    Diabetes-associated hyperglycemia causes glycation of proteins at reactive amino groups, which can adversely affect protein function Although the effects of glycation on soluble proteins are well characterized, there is no information regarding membrane-associated proteins, mainly because of the lack of reproducible methods to determine protein glycation in vivo. The current study was conducted to establish such a method and to compare the glycation levels of membrane-associated proteins deri...

  5. Glycation inhibits trichloroacetic acid (TCA)-induced whey protein precipitation

    Science.gov (United States)

    Four different WPI saccharide conjugates were successfully prepared to test whether glycation could inhibit WPI precipitation induced by trichloroacetic acid (TCA). Conjugates molecular weights after glycation were analyzed with SDS-PAGE. No significant secondary structure change due to glycation wa...

  6. RAGE genetic polymorphisms are associated with risk, chemotherapy response and prognosis in patients with advanced NSCLC.

    Directory of Open Access Journals (Sweden)

    Xiang Wang

    Full Text Available AIM: To explore the association between genetic polymorphisms of the receptor for advanced glycation end-products (RAGE and susceptibility, chemotherapy response rate and prognosis of non-small cell lung cancer (NSCLC. METHOD: This is a prospective study in which 562 patients with NSCLC and 764 healthy controls were enrolled. Three RAGE genetic polymorphisms, namely, -429T/C, -374T/A and 82G/S were genotyped. Platinum-based chemotherapy was given to 432 subjects with advanced inoperable NSCLC and their responses to chemotherapy were evaluated. RESULTS: All the polymorphic genotypes of RAGE polymorphisms were associated with susceptibility for NSCLC. Only the 82G/S polymorphisms denoted a significant difference between responders and non-responders to chemotherapy. The 82SS genotype and 82S allele distribution not only increased the NSCLC risk, but also was associated with a lower chemotherapy response rate and poor prognosis, indicated by overall survival and progression free survival. CONCLUSION: The 82G/S genetic polymorphism of RAGE gene might be used as a genetic marker to screen for patients sensitive to thermotherapy and to predict the prognosis of NSCLC.

  7. Association of plasma proteins at multiple stages of glycation and antioxidant status with erythrocyte oxidative stress in patients with type 2 diabetes.

    Science.gov (United States)

    Tupe, R S; Diwan, A G; Mittal, V D; Narayanam, P S; Mahajan, K B

    2014-01-01

    This study examines the individual stages of plasma protein glycation, antioxidant status and their association with erythrocyte oxidative stress in patients with type 2 diabetes mellitus (T2DM). Study was carried out on blood from 70 patients with T2DM and 40 healthy age- and gender-matched volunteers. Biomarkers of plasma protein glycation (fructosamine, protein carbonyls, advanced glycation end products [AGEs], amyloid), antioxidant status (thiols, total antioxidant capacity and erythrocyte oxidative parameters), osmotic fragility, lipid peroxidation (LPO), reduced glutathione (GSH) and catalase were determined. Plasma glycation markers were higher in T2DM patients than in healthy volunteers: fructosamine 578 vs. 525 micromol/mL; carbonyl 21.23 vs. 18.84 nmol/mg protein (P glycation markers, positive correlations were evident between fructosamine and amyloid (r = 0.350, P glycation markers showed negative correlation with plasma antioxidant status while positive correlation was demonstrated between erythrocytes fragility and AGEs and amyloid. Erythrocyte LPO levels correlated positively with amyloid. These data suggest that increased levels of multiple plasma protein glycation products in T2DM patients play a key role in reduced plasma antioxidant status and amplified erythrocyte oxidative damage.

  8. 晚期糖基化终产物诱导人脐静脉内皮细胞ERM蛋白磷酸化的机制%Mechanism of advanced glycation end products-stimulated phosphorylation of ERM protein in human umbilical vein endothelial cells

    Institute of Scientific and Technical Information of China (English)

    王占华; 郭晓华; 陈波; 李强; 王吉萍; 朱平; 王陵军; 吴炜; 黄巧冰

    2010-01-01

    采用免疫荧光细胞化学和Western印迹法,探讨晚期糖基化终产物(AGE)对人脐静脉内皮细胞的ERM(ezrin/radixint/moesin)蛋白磷酸化水平和定位的影响及其机制.AGE以时间和剂量依赖性地增加ERM蛋白磷酸化水平(均P<0.05),并促进其转位至胞浆内.AGE通过与其受体结合刺激ERM蛋白的磷酸化,Rho激酶及p38丝裂原活化蛋白激酶通路参与了此过程.%The effects of advanced glycation end products(AGE)on phosphorylation of ezrin/radixin/ moesin(ERM)protein in human umbilical vein endothelial ceils were detected by immunofluorescence cytochemistry and its mechanism was explored.AGE stimulated the phosphorylation of ERM protein in dose-and time-dependent manners(all P<0.05),which was involved in AGE receptor,Rho kinase,and p38 mitogen-activated protein kinase pathways.

  9. A New Locus for Skin Intrinsic Fluorescence in Type 1 Diabetes also Associated with Blood and Skin Glycated Proteins

    NARCIS (Netherlands)

    Roshandel, Delnaz; Klein, Ronald; Klein, Barbara E K; Wolffenbuttel, Bruce H R; van der Klauw, Melanie M; van Vliet-Ostaptchouk, Jana V; Atzmon, Gil; Ben-Avraham, Danny; Crandall, Jill P; Barzilai, Nir; Bull, Shelley B; Canty, Angelo J; Hosseini, S Mohsen; Hiraki, Linda T; Maynard, John; Sell, David R; Monnier, Vincent M; Cleary, Patricia A; Braffett, Barbara H; Paterson, Andrew D

    2016-01-01

    Skin fluorescence (SF) non-invasively measures advanced glycation end products (AGEs) in the skin and is a risk indicator for diabetic complications. N-acetyltransferase 2 (NAT2) is the only known locus influencing SF. We aimed to identify additional genetic loci influencing SF in type 1 diabetes (T

  10. New Locus for Skin Intrinsic Fluorescence in Type 1 Diabetes Also Associated With Blood and Skin Glycated Proteins

    NARCIS (Netherlands)

    Roshandel, Delnaz; Klein, Ronald; Klein, Barbara E. K.; Wolffenbuttel, Bruce H. R.; van der Klauw, Melanie M.; van Vliet-Ostaptchouk, Jana V.; Atzmon, Gil; Ben-Avraham, Danny; Crandall, Jill P.; Barzilai, Nir; Bull, Shelley B.; Canty, Angelo J.; Hosseini, S. Mohsen; Hiraki, Linda T.; Maynard, John; Sell, David R.; Monnier, Vincent M.; Cleary, Patricia A.; Braffett, Barbara H.; Paterson, Andrew D.

    2016-01-01

    Skin fluorescence (SF) noninvasively measures advanced glycation end products (AGEs) in the skin and is a risk indicator for diabetes complications. N-acetyltransferase 2 (NAT2) is the only known locus influencing SF. We aimed to identify additional genetic loci influencing SF in type 1 diabetes (T1

  11. Improved Methods for the Enrichment and Analysis of Glycated Peptides

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qibin; Schepmoes, Athena A; Brock, Jonathan W; Wu, Si; Moore, Ronald J; Purvine, Samuel O; Baynes, John; Smith, Richard D; Metz, Thomas O

    2008-12-15

    Non-enzymatic glycation of tissue proteins has important implications in the development of complications of diabetes mellitus. Herein we report improved methods for the enrichment and analysis of glycated peptides using boronate affinity chromatography and electron transfer dissociation mass spectrometry, respectively. The enrichment of glycated peptides was improved by replacing an off-line desalting step with an on-line wash of column-bound glycated peptides using 50 mM ammonium acetate. The analysis of glycated peptides by MS/MS was improved by considering only higher charged (≥3) precursor-ions during data-dependent acquisition, which increased the number of glycated peptide identifications. Similarly, the use of supplemental collisional activation after electron transfer (ETcaD) resulted in more glycated peptide identifications when the MS survey scan was acquired with enhanced resolution. In general, acquiring ETD-MS/MS data at a normal MS survey scan rate, in conjunction with the rejection of both 1+ and 2+ precursor-ions, increased the number of identified glycated peptides relative to ETcaD or the enhanced MS survey scan rate. Finally, an evaluation of trypsin, Arg-C, and Lys-C showed that tryptic digestion of glycated proteins was comparable to digestion with Lys-C and that both were better than Arg-C in terms of the number glycated peptides identified by LC-MS/MS.

  12. Anti-glycation and anti-oxidation properties of Capsicum frutescens and Curcuma longa fruits: possible role in prevention of diabetic complication.

    Science.gov (United States)

    Khan, Ibrar; Ahmad, Haroon; Ahmad, Bashir

    2014-09-01

    The accumulation of advanced glycationend products (AGE's) in the body, due to the non-enzymatic glycation of proteins is associated with several pathological conditions like aging and diabetes mellitus. Hence a plant having anti-glycation and anti-oxidation potentials may serve as therapeutic agent for diabetic complications and aging. In this study the anti-glycation and anti-oxidation properties of crude methanolic extracts of fruits of Capsicum frutescens and Curcuma longa were investigated. Among the two C. frutescens had more anti-glycation ability with a minimum inhibitory concentration (MIC50) of 90βg/mLas compared to 324βg/mL MIC50 of C. longa. Curcuma longa had the more anti-oxidation potential i.e. 35.01, 30.83 and 28.08% at 0.5mg, 0.25mg and 0.125mg respectively.

  13. The effect of glycation on arterial microstructure and mechanical response.

    Science.gov (United States)

    Stephen, Elizabeth A; Venkatasubramaniam, Arundhathi; Good, Theresa A; Topoleski, L D T

    2014-08-01

    Like engineered materials, an artery's biomechanical behavior and function depend on its microstructure. Glycation is associated with both normal aging and diabetes and has been shown to increase arterial stiffness. In this study we examined the direct effect of glycation on the mechanical response of intact arteries and on the mechanical response and structure of elastin isolated from the arteries. Samples of intact arteries and isolated elastin were prepared from porcine aortas and glycated. The mechanical response of all samples was completed using a uniaxial material test system. Glycation levels were measured using ELISA. A confocal microscope was used to image differences in the structure of the glycated and untreated elastin fibers. We found that, under the conditions used in this study, glycation led to decreased stiffness of elastin isolated from arteries, which was associated with a thinning of elastin fibers as imaged by confocal microscopy. We observed no effect of glycation on collagen fibers under our treatment conditions. These results suggest that glycation leads to weakening of the elastin component of arteries that could contribute to vascular defects seen in diabetes and aging. Prevention of glycation reactions may be an important consideration for vascular health later in life.

  14. The structural feature surrounding glycated lysine residues in human hemoglobin.

    Science.gov (United States)

    Ito, Shigenori; Nakahari, Takashi; Yamamoto, Daisuke

    2011-06-01

    Complications derived from diabetes mellitus are caused by nonenzymatic protein glycation at the specific sites. LC/MS/MS was performed for the identification of the tryptic peptides of glycated hemoglobins using glyceraldehyde. After the identification of the glycation or non-glycation site, computer analysis of the structure surrounding the sites was carried out using PDB data (1BZ0). Five glycated lysine residues (Lys-16(α), -56(α), -8(β), -82(β), and -144(β)) and four non-glycated lysine residues (Lys-7(α), -40(α), -99(α), and -132(β)) were identified. The non-glycated lysine residues, Lys-7(α), -40(α), and -132(β), are most likely to form electrostatic interactions with the β carboxyl group of Asp-74(α), C-terminal His-146(β), and Glu-7(β) by virtue of their proximity, which is 2.67-2.91 Å (N-O). Additionally, there are histidine residues within 4.55-7.38 Å (N-N) around eight sites except for Lys-7(α). We conclude that the following factors seem to be necessary for glycation of lysine residues: (i) the apparent absence of aspartate or glutamate residues to inhibit the glycation reaction by forming an electrostatic interaction, (ii) the presence of histidine residues for acid-base catalysis of the Amadori rearrangement, and (iii) the presence of an amino acid residue capable of stabilizing a phosphate during proton transfer.

  15. Whole wheat bread: Effect of bran fractions on dough and end-product quality

    Science.gov (United States)

    Consumption of whole-wheat based products is encouraged due to its important nutritional elements that beneficial to human health. However, processing of whole-wheat based products, such as whole-wheat bread, results in poor end-product quality. Bran was postulated as the major problem. In this stud...

  16. 细胞内活性氧在糖基化终末产物促人腹膜间皮细胞分泌单核细胞趋化因子1中的作用%The role of reactive oxygen species in the promotion of monocyte chemoattractant protein-1(MCP-1) production by advanced glycation end products-human serum albumin(AGE-HSA)in human peritoneal mesothelial cells

    Institute of Scientific and Technical Information of China (English)

    洪富源; 孙芳; 刘军; 姚建; 黄一新; 唐知还

    2010-01-01

    目的 观察糖基化终末产物(advanced glycation end products,AGEs)对人腹膜间皮细胞(human peritoneal mesothelial cell,HPMC)分泌单核细胞趋化蛋白1(monocyte chemoattractant protein-1,MCP1)的作用及细胞内活性氧族(reactive oxygen species,ROS)在其中的作用.方法 分别用不同浓度的糖基化人血清白蛋白(advanced glycation end products-human serum albumin,AGE-HSA)及抗氧化剂N-乙酰-L-半胱氨酸(N-acetyl-L-cysteine,NAC)作用于细胞,用逆转录多聚酶链反应(RT-PCR)法和酶联免疫吸附法(ELISA)测定HPMC中MCP-1的表达;再以氧化敏感的荧光染料2,7-二氢二氯荧光素(2.7-dichlorofluorescin,DCFH)染色,流式细胞仪测定ROS强度.结果 AGE-HSA能使细胞内ROS水半明显升高,呈现浓度依赖效应;AGE-HSA同时以时效和量效方式促进HPMC中MCP-1的表达;而NAC能够明显抑制AGE-HSA 所导致的细胞内ROS升高,同时抑制HPMC中MCP-1的分泌.结论 AGE-HSA 可能部分通过诱导细胞内ROS,促进HPMC 表达MCP-1.

  17. Effects of periodontal initial therapy on advanced glycation end products of type 2 diabetes mellitus patients with periodontitis%牙周基础治疗对Ⅱ型糖尿病伴牙周炎病人糖基化终产物的影响

    Institute of Scientific and Technical Information of China (English)

    汪涛; 房明; 丁鳌; 曹敏; 马志伟; 王勤涛

    2011-01-01

    目的:观察牙周基础治疗对Ⅱ型糖尿病伴慢性牙周炎病人牙周组织和血清中糖基化终产物(advanced glycation end of products,AGEs)变化的长期影响.方法:诊断为Ⅱ型糖尿病并伴有中等程度以上牙周炎的病人30例,分为进行牙周基础治疗的干预组15例(DM1组),未进行牙周基础治疗的未干预组15例(DM2组);分别在初诊和每次复诊治疗前记录2组的探诊深度(probing depth,PD)、附着丧失(attachment loss,AL)、空腹血糖、AGEs指标.结果:经牙周基础治疗后,DM1组牙周临床指标均有明显改善;2组AGEs水平有不同程度升高(P<0.05);DM1组第21个月AGEs水平显著低于DM2组,有统计学意义(P<0.05).结论:牙周基础治疗对Ⅱ型糖尿病伴慢性牙周炎病人的PD、AL、血糖水平、AGEs水平有显著的改善(P<0.05),并且有助于长期稳定.%AIM : To observe the effect of periodontal initial therapy on the changes of advanced glycation end products ( AGEs) and periodontal status in type 2 diabetes mellitus patients with periodontitis.METHODS : Thirty type 2 diabetes patients with periodontitis were enrolled in this study.The patients were divided into two groups with 15 subjects in each group: DMI group with periodontal therapy and DM2 group with no periodontal intervention.Periodontal probing depth ( PD) , clinical attachment loss ( AI.) , serum glucose level and AGFs were recorded from first visit to twenty-first month.RESULTS: After periodontal initial therapy, all of periodontal clinical indexes in DMI group were significantly improved ( P < 0.05 ).Both groups showed significandy elevated levels of AGEs ( P < 0.05 ).The level of AGEs in DM1 group was significantly less than that of the DM2 group at month 21 (P <0.05).CONCLUSION: Periodontal initial therapy is effective to decrease the values of PD, AL and blood glucose and maintains their long-term stability.

  18. 人巨细胞病毒和糖基化终产物共同作用对血管内皮细胞的影响%Co-effects of human cytomegalovirus infection and advanced glycation end products on vascular endothelial cells

    Institute of Scientific and Technical Information of China (English)

    李树英; 刘娟; 吴建敏; 周亚滨; 张风雷; 程轶喆; 于晗; 齐眉; 唐伟; 王红

    2007-01-01

    目的:观察人巨细胞病毒(human cytomegalovirus,HCMV)和糖基化终产物(advanced glycation end products, AGEs)共同作用对血管内皮细胞(vein endothelial cells,ECV)氧化应激的影响及对糖基化终产物受体(the receptor for advanced glycation end products, RAGE)表达的影响,明确HCMV和AGEs在致内皮细胞损伤作用中是否具有协同效应,探讨HCMV和AGEs致动脉粥样硬化 (AS)发生和发展的可能机制.方法:用HCMV和AGEs分别及共同作用于ECV,将实验对象分为:对照组、HCMV组、牛血清白蛋白(BSA)组、AGEs组、AGEs+HCMV组5组;用激光共聚焦显微镜检测细胞内活性氧(ROS)的改变;采用RT-PCR方法检测血管内皮细胞RAGEmRNA的表达.结果:HCMV感染ECV后,对照组荧光强度和BSA组荧光强度均较弱,两组间比较差异无统计学意义(P>0.05);AGEs组和HCMV组荧光强度强于对照组(P<0.01);AGEs+HCMV组荧光强度高于AGEs组和HCMV组(P<0.05),两者联合作用存在协同效应.对照组和BSA组ECV细胞RAGEmRNA均有低水平表达,两组之间比较无差异(P>0.05);AGEs组和HCMV感染组RAGEmRNA表达量高于对照组(P<0.01);AGEs+HCMV组表达量高于AGEs组和HCMV组(P<0.01).在相同病毒滴度感染的情况下,随AGEs浓度增加RAGEmRNA的表达增高,呈浓度依赖性;在相同AGEs浓度作用时,随HCMV感染滴度增加RAGEmRNA的表达水平升高,呈滴度依赖性.各组之间比较差异有统计学意义(P<0.05).结论:HCMV和AGEs均能够增强血管内皮细胞氧化应激,促进RAGEmRNA的表达,两者共同作用时呈协同效应.HCMV和AGEs有可能通过协同增强氧化应激、进一步上调RAGEmRNA的表达,介导血管内皮细胞的炎症反应,促进动脉粥样硬化的发生、发展.

  19. Semi-purification procedures of prions from a prion-infected brain using sucrose has no influence on the nonenzymatic glycation of the disease-associated prion isoform.

    Science.gov (United States)

    Choi, Yeong-Gon; Kim, Jae-Il; Choi, Eun-Kyoung; Carp, Richard I; Kim, Yong-Sun

    2016-01-01

    Previous studies have shown that the Nε-carboxymethyl group is linked to not only one or more N-terminal Lys residues but also to one or more Lys residues of the protease-resistant core region of the pathogenic prion isoform (PrPSc) in prion-infected brains. Using an anti-advanced glycation end product (AGE) antibody, we detected nonenzymatically glycated PrPSc (AGE-PrPSc) in prion-infected brains following concentration by a series of ultracentrifugation steps with a sucrose cushion. In the present study, the levels of in vitro nonenzymatic glycation of PrPSc using sucrose were investigated to determine whether sucrose cushion can artificially and nonenzymatically induce in vitro glycation during ultracentrifugation. The first insoluble pellet fraction following the first ultracentrifugation (PU1st) collected from 263K scrapie-infected brains was incubated with sucrose, glucose or colloidal silica coated with polyvinylpyrrolidone (percoll). None of the compounds in vitro resulted in AGE-PrPSc. Nonetheless, glucose and percoll produced AGEs in vitro from other proteins within PU1st of the infected brains. This reaction could lead to the AGE-modified polymer(s) of nonenzymatic glycation-prone protein(s). This study showed that PrPSc is not nonenzymatically glycated in vitro with sucrose, glucose or percoll and that AGE-modified PrPSc can be isolated and enriched from prion-infected brains.

  20. Moringa oleifera aqueous leaf extract inhibits reducing monosaccharide-induced protein glycation and oxidation of bovine serum albumin.

    Science.gov (United States)

    Nunthanawanich, Pornpimon; Sompong, Weerachat; Sirikwanpong, Sukrit; Mäkynen, Kittana; Adisakwattana, Sirichai; Dahlan, Winai; Ngamukote, Sathaporn

    2016-01-01

    Advanced glycation end products (AGEs) play an important factor for pathophysiology of diabetes and its complications. Moringa oleifera is one of the medicinal plants that have anti-hyperglycemic activity. However, anti-glycation property of Moringa oleifera leaf extract on the different types of reducing monosaccharides-induced protein glycation has not been investigated. Therefore, the aim of this study was to examine the protective effect of Moringa oleifera aqueous leaf extract (MOE) on reducing sugars-induced protein glycation and protein oxidation. Total phenolic content of MOE was measured using the Folin-Ciocalteu method. Bovine serum albumin was incubated with 0.5 M of reducing sugars (glucose or fructose) with or without MOE (0.5-2.0 mg/mL) for 1, 2, 3 and 4 weeks. The results found that total phenolic content was 38.56 ± 1.50 mg gallic acid equivalents/g dry extract. The formation of fluorescent and non-fluorescent AGEs [N (ε)-(carboxymethyl) lysine (CML)] and the level of fructosamine were determined to indicate protein glycation, whereas the level of protein carbonyl content and thiol group were examined for protein oxidation. MOE (0.5-2.0 mg/mL) significantly inhibited the formation of fluorescent, N (ε)-CML and markedly decreased fructosamine level (P < 0.05). Moreover, MOE significantly prevented protein oxidation manifested by reducing protein carbonyl and the depletion of protein thiol in a dose-dependent manner (P < 0.05). Thus, the findings indicated that polyphenols containing in MOE have high potential for decreasing protein glycation and protein oxidation that may delay or prevent AGE-related diabetic complications.

  1. Evaluation of a reference material for glycated haemoglobin

    NARCIS (Netherlands)

    Weykamp, CW; Penders, TJ; Muskiet, FAJ; vanderSlik, W

    1996-01-01

    The use of lyophilized blood as a reference material for glycated haemoglobin was investigated with respect to IFCC criteria for calibrators and control materials. Ninety-two laboratories, using 11 methods, detected no changes in glycated haemoglobin content when the lyophilizate was stored for one

  2. Electrocatalytic assay for monitoring methylglyoxal-mediated protein glycation.

    Science.gov (United States)

    Havlikova, Marika; Zatloukalova, Martina; Ulrichova, Jitka; Dobes, Petr; Vacek, Jan

    2015-02-03

    Protein glycation is a complex process that plays an important role in diabetes mellitus, aging, and the regulation of protein function in general. As a result, current methodological research on proteins is focused on the development of novel approaches for investigating glycation and the possibility of monitoring its modulation and selective inhibition. In this paper, a first sensing strategy for protein glycation is proposed, based on protein electroactivity measurement. Concretely, the label-free method proposed is based on the application of a constant-current chronopotentiometric stripping (CPS) analysis at Hg-containing electrodes. The glycation process was monitored as the decrease in the electrocatalytic protein signal, peak H, observed at highly negative potentials at around -1.8 V (vs Ag/AgCl3 M KCl), which was previously ascribed to a catalytic hydrogen evolution reaction (CHER). Using this method, a model protein bovine serum albumin was investigated over 3 days of incubation with the glycation agent methylglyoxal in the absence or presence of the glycation inhibitor aminoguanidine (pimagedine). The electrochemical methodology presented here could open up new possibilities in research on protein glycation and oxidative modification. The methodology developed also provides a new option for the analysis of protein intermolecular interactions using electrochemical sensors, which was demonstrated by the application of a silver solid amalgam electrode (AgSAE) for monitoring the glycation process in samples of bovine serum albumin, human serum albumin, and lysozyme.

  3. The initial noncovalent binding of glucose to human hemoglobin in nonenzymatic glycation.

    Science.gov (United States)

    Clark, Shelley L D; Santin, Angela E; Bryant, Priscilla A; Holman, Rw; Rodnick, Kenneth J

    2013-11-01

    Mechanisms for nonenzymatic protein glycation have been extensively studied albeit with an emphasis at the later stages that gives rise to advanced glycation end products. No detailed investigation of the initial, noncovalent binding of d-glucose to human hemoglobin A (HbA) exists in the literature. Although anionic molecules 2,3-bisphosphoglycerate (BPG), inorganic phosphate (Pi) and HCO3(-) have been implicated in the latter stages of glycation, their involvement at the initial binding of glucose to HbA has not yet been assessed. Results from this computational study involving crystal structures of HbA predict that the transient, ring-opened glucose isomer, assumed to be critical in the later stages of glycation, is not directly involved in initial binding to the β-chain of HbA. All the five structures of glucose generated upon mutorotation will undergo reversible, competitive and slow binding at multiple amino acid residues. The ring-opened structure is most likely generated from previously bound pyranoses that undergo mutarotation while bound. BPG, Pi and HCO3(-) also reversibly bind to HbA with similar energies as glucose isomers (~3-5 kcal/mol) and share common binding sites with glucose isomers. However, there was modest amino acid residue selectivity for binding of certain anionic molecules (1-3 regions) but limited selectivity for glucose structures (≥ 7 regions). The clinical difference between average blood glucose and predicted HbA1c, and the presence of unstable HbA-glucose complexes may be more fully explained by initial noncovalent binding interactions and different concentrations of BPG, Pi and HCO3(-) in serum vs. erythrocytes.

  4. Characterization of Clostridium thermocellum strains with disrupted fermentation end-product pathways

    Energy Technology Data Exchange (ETDEWEB)

    Van Der Veen, Douwe [ORNL; Lo, Jonathan [Dartmouth College; Brown, Steven D [ORNL; Johnson, Courtney M [ORNL; Tschaplinski, Timothy J [ORNL; Martin, Madhavi Z [ORNL; Engle, Nancy L [ORNL; Van den Berg, Robert A [Katholieke University Leuven, Belgium; Argyros, Aaron [Mascoma Corporation; Caiazza, Nicky [Mascoma Corporation; Guss, Adam M [ORNL; Lynd, Lee R [Thayer School of Engineering at Dartmouth

    2013-01-01

    Clostridium thermocellum is a thermophilic, cellulolytic anaerobe that is a candidate microorganism for industrial biofuels production. Strains with mutations in genes associated with production of L-lactate (Dldh) and/or acetate (Dpta) were characterized to gain insight into the intracellular processes that convert cellobiose to ethanol and other fermentation end-products. Cellobiose-grown cultures of the Dldh strain had identical biomass accumulation, fermentation end-products, transcription profile, and intracellular metabolite concentrations compared to its parent strain (DSM1313 Dhpt Dspo0A). The Dpta-deficient strain grew slower and had 30 % lower final biomass concentration compared to the parent strain, yet produced 75% more ethanol. A Dldh Dpta double-mutant strain evolved for faster growth had a growth rate and ethanol yield comparable to the parent strain, whereas its biomass accumulation was comparable to Dpta. Free amino acids were secreted by all examined strains, with both Dpta strains secreting higher amounts of alanine, valine, isoleucine, proline, glutamine, and threonine. Valine concentration for Dldh Dpta reached 5 mM by the end of growth, or 2.7 % of the substrate carbon utilized. These secreted amino acid concentrations correlate with increased intracellular pyruvate concentrations, up to sixfold in the Dpta and 16-fold in the Dldh Dpta strain. We hypothesize that the deletions in fermentation end-product pathways result in an intracellular redox imbalance, which the organism attempts to relieve, in part by recycling NADP* through increased production of amino acids.

  5. Effects of glycation on meloxicam binding to human serum albumin

    Science.gov (United States)

    Trynda-Lemiesz, Lilianna; Wiglusz, Katarzyna

    2011-05-01

    The current study reports a binding of meloxicam a pharmacologically important new generation, non-steroidal anti-inflammatory drug to glycated form of the human serum albumin (HSA). The interaction of the meloxicam with nonglycated and glycated albumin has been studied at pH 7.4 in 0.05 M sodium phosphate buffer with 0.1 M NaCl, using fluorescence quenching technique and circular dichroism spectroscopy. Results of the present study have shown that the meloxicam could bind both forms of albumin glycated and nonglycated at a site, which was close to the tryptophan residues. Similarly, how for native albumin glycated form has had one high affinity site for the drug with association constants of the order of 10 5 M -1. The glycation process of the HSA significantly has affected the impact of the meloxicam on the binding of other ligands such as warfarin and bilirubin. The affinity of the glycated albumin for bilirubin as for native albumin has been reduced by meloxicam but observed effect was weaker by half (about 20%) compared with nonglycated albumin. In contrast to the native albumin meloxicam binding to glycated form of the protein only slightly affected the binding of warfarin. It seemed possible that the effects on warfarin binding might be entirely attributable to the Lys 199 modification which was in site I.

  6. Effect of Advanced Glycation End Products on Expression of Urotensin Ⅱ and G-Protein-Couple Receptor mRNAs in Rat Mesangial Cells%糖基化终末产物对大鼠肾小球系膜细胞尾加压素Ⅱ及G蛋白偶联受体mRNA表达的影响

    Institute of Scientific and Technical Information of China (English)

    赵岩; 林风武; 李才

    2010-01-01

    目的 观察不同浓度糖基化终末产物(Advanced glycation end products,AGEs)及AGEs作用不同时间对大鼠肾小球系膜细胞尾加压素Ⅱ(UrotensinⅡ,UⅡ)及G蛋白偶联受体(G-protein-couple receptor,GPR14)mRNA表达的影响.方法 制备AGE-BSA,体外培养大鼠肾小球系膜细胞(Mesangial cells,MC),加入不同浓度的AGE-BSA(终浓度分别为0、25、50、100和200 mg/L),37℃孵育24 h;加入100 mg/L AGE-BSA,分别培养0、2、8、16和24 h,以不含葡萄糖的BSA作为对照.收集细胞,采用RT-PCR检测各组MC UⅡ及GPR14 mRNA的表达.结果 AGE-BSA各组MC UⅡ及GPR14 mRNA的表达量均随AGEs浓度的增加而增加,50、100和200 mg/L与0 mg/L组比较,差异有统计学意义(P<0.05);100 mg/L AGE-BSA各组MC UⅡ及GPR14 mRNA的表达量随着作用时间的延长而增加,作用8、16、24 h组与0 h组比较,差异有统计学意义(P<0.05).BSA组MC UⅡ及GPR14 mRNA的表达量无明显增加(P>0.05).结论 AGEs能上调大鼠MC UⅡ及GPR14 mRNA的表达.

  7. Water Extraction of Cinnamon Proanthocyanidins and Its Inhibitory Effect on the Formation of Advanced Glycation End Products%肉桂原花青素的提取及其对高级糖基化终产物形成的抑制作用

    Institute of Scientific and Technical Information of China (English)

    黎超; 毛超伦; 雍克岚

    2012-01-01

    One factor-at-a-time and orthogonal array design methods were used to determine the optimal operating conditions for water extraction of proanthocyanidins from cinnamon(CPAs).Nine types of macroporous adsorption resin were compared for their effectiveness in adsorbing and desorbing CPAs.Meanwhile,the in vitro inhibitory effect of CPAs on the formation of advanced glycation end products(AGEs) was tested.The optimal extraction conditions were found to be 2 h of extraction at 60 ℃ with acidic water at pH 5.0(adjusted with sodium acetate-acetic acid buffe) at a liquid/solid ratio of 14:1(mL/g).Under these conditions,the extraction rate of CPAs was 14.27 mg/g.LSA-21 resin was the most effective in purifying CPAs.CPAs had strong inhibitory activity on the formation of AGEs with an IC50 of 45.93μg/mL,which was higher than that of the positive control aminoguanidimine.%通过单因素和正交试验确定肉桂中原花青素(proanthocyanidins of cinnamon,CPAs)最佳水提工艺条件,比较9种大孔吸附树脂对CPAs的吸附与解吸性能,对CPAs进行体外蛋白非酶糖化抑制实验。结果表明:最佳提取条件为液料比14:1(mL/g)、提取温度60℃、pH5.0、提取时间2h,CPAs提取得率为14.27mg/g,LSA-21大孔吸附树脂分离纯化CPAs效果最佳。该肉桂提取物对高级糖基化终产物的形成具有很好的抑制活性,其IC50为45.93μg/mL,高于阳性对照氨基胍。

  8. Influence of advanced glycation end products on prostacyclin and endothelin-1 secretion from human vascular endothelial cells%糖基化终末产物对人内皮细胞分泌前列环素和内皮素-1的影响

    Institute of Scientific and Technical Information of China (English)

    赵保明; 李凤良; 宋喜明

    2011-01-01

    Objective To investigate the influence of advanced glycation end products (AGES) on prostacyclin (PGI2) and endothelin-1 ( ET-1) secretion from human umbilical vein endothelial cells (HUVEC), and the effect of a-lipoic acid(a-LPA) on it. Methods HUVEC were obtained by enzyme digestion and primary culture, and divided into the normal control group, the AGES group, the normal + AGES group, and the AGES + a-LPA group. PGI2 and ET-1 in culture media were assayed by radioimmunoassay( RIA) when HUVEC were cultured for 24,48 and 72 hours. Results ①The content of PGI2 in the AGES group was lower than that in the normal control group( P < 0.05), while the content of ET-1 was higher(p <0.05). ②The content of PGI2 in the AGES + a-LPA group was higher than that in the AGES group (P < 0.05), while the content of ET-1 was lower( P < 0.01). Conclusion AGES can injure vascular endothelial cells, while a-LPA can diminish the injury, which indicates that antioxidants can protect vascular endothelial cells.%目的 了解糖基化终末产物(AGEs)对人内皮细胞分泌前列环素(PGI2)和内皮素-1(ET-1)的影响,以及α-硫辛酸(α-LPA)对其的影响.方法 采用酶消化法收集人脐静脉内皮细胞,经原代培养后随机分为4组:正常对照组、AGEs组、正常+AGEs组和AGEs+α-LPA组;放免法测定培养24、48、72 h时培养基中的PGI2和ET-1含量.结果 ①AGEs组较正常对照组PGI2显著下降(P<0.05),ET-1显著升高(P<0.05);②AGEs+α-LPA组较AGEs组PGI2显著升高(P<0.05),ET-1显著下降(P<0.01).结论 AGEs对血管内皮细胞有损伤作用,α-LPA可减轻这种损伤,提示抗氧化剂可用于保护血管内皮细胞.

  9. Inhibitory Effect of Artemisia selengensis Straw Flavonoids on the Formation of Advanced Glycation End Products (AGEs)%芦蒿秸秆黄酮类化合物对晚期蛋白质糖基化终末产物形成的抑制作用

    Institute of Scientific and Technical Information of China (English)

    邓荣华; 陆敏; 夏秋琴; 李晓明; 孔阳辉; 吕丽爽

    2014-01-01

    通过建立牛血清白蛋白-丙酮醛(bovine serum albumin-methylglyoxal,BSA-MGO)的蛋白质糖基化反应模型,用荧光法测定体外晚期蛋白质糖基化终末产物(advanced glycation end products,AGEs)的含量,探讨芦蒿秸秆黄酮类化合物对AGEs形成的抑制效果,并对木犀草素的作用途径进行探索.结果表明:芦蒿秸秆总黄酮浸膏经AB-8树脂分离后共收集到4组含有黄酮的洗脱组分(F-10、F-30、F-50、F-70)对AGEs的形成均具有抑制作用,抑制效果由强到弱为依次为F-50>F-30>F-10>F-70,此结果与F-30和F-50分离纯化得到的黄酮成分芦丁和木犀草素具有较好的AGEs抑制效果相一致.同时发现,芦蒿秸秆对AGEs形成的抑制效果与总黄酮含量存在显著的线性关系.另外,将木犀草素与MGO的反应产物进行分离纯化,高效液相色谱-质谱联用分析显示:木犀草素作用途径为通过捕获MGO,形成木犀草素-MGO加和物来抑制AGEs的形成.芦蒿秸秆黄酮类化合物可抑制体外蛋白质糖基化反应的活性预示其可以作为AGEs的天然抑制剂来预防和减轻糖尿病及其并发症.

  10. STAT5 activation induced by diabetic LDL depends on LDL glycation and occurs via src kinase activity.

    Science.gov (United States)

    Brizzi, Maria Felice; Dentelli, Patrizia; Gambino, Roberto; Cabodi, Sara; Cassader, Maurizio; Castelli, Ada; Defilippi, Paola; Pegoraro, Luigi; Pagano, Gianfranco

    2002-11-01

    Advanced glycation end products (AGEs) have been implicated in the accelerated vascular injury occurring in diabetes. We recently reported that LDL prepared from type 2 diabetic patients (dm-LDL), but not normal LDL (n-LDL) triggered signal transducers and activators of transcription STAT5 activation and p21(waf) expression in endothelial cells (ECs). The aims of the present study were to investigate the role of LDL glycation in dm-LDL- mediated signals and to analyze the molecular mechanisms leading to STAT5 activation. We found that glycated LDL (gly-LDL) triggered STAT5 activation, the formation of a prolactin inducible element (PIE)-binding complex containing STAT5, and increased p21(waf) expression through the activation of the receptor for AGE (RAGE). We also demonstrated that dm-LDL and gly-LDL, but not n-LDL treatment induced the formation of a stable complex containing the activated STAT5 and RAGE. Moreover, gly-LDL triggered src but not JAK2 kinase activity. Pretreatment with the src kinase inhibitor PP1 abrogated both STAT5 activation and the expression of p21(waf) induced by gly-LDL. Consistently, gly-LDL failed to activate STAT5 in src(-/-) fibroblasts. Collectively, our results provide evidence for the role of glycation in dm-LDL-mediated effects and for a specific role of src kinase in STAT5-dependent p21(waf) expression.

  11. Comparisons of home blood glucose testing and glycated protein measurements.

    Science.gov (United States)

    Lee, P D; Sherman, L D; O'Day, M R; Rognerud, C L; Ou, C N

    1992-04-01

    We examined the relationships between 4 glycated protein assays and home blood glucose monitoring (HBGM) in 26 children with poorly-controlled insulin-dependent diabetes mellitus (IDDM) during a period of improved management. At 2 week intervals for 6 visits (12 weeks in total), HBGM records were collected and a blood sample was obtained for measurement of glycated proteins and glucose. Assays included glycated hemoglobin (GHb) and glycated serum proteins (GP) by boronate affinity chromatography, hemoglobin A1C by PolyCAT A high performance liquid chromatography (HAC) and fructosamine (FA). All 4 glycated protein levels declined significantly over the 12 week period. Significant correlations between the glycated proteins and HBGM were observed over 2 week intervals. None of the 4 assays were affected by the glucose level in the sample. Changes in mean HBGM readings over 2 week intervals were correlated with both FA and GP with wide prediction intervals. Over cumulative 2 week intervals, which may more accurately reflect longitudinal trends, all 4 glycated proteins were correlated with mean HBGM readings. At each cumulative interval, GHb and GP showed the largest variation with MBG, while FA showed the least variation with MBG. Our data indicate that of the 4 assays tested, FA has limited clinical values as compared to other glycated protein assays, whereas assays based on boronate affinity chromatography (GHb and GP) provide the most useful clinical indicators of short-term changes in glycemic control. The clinical utility of a new HPLC method for determination of glycated hemoglobins is also demonstrated.

  12. Recent Topics in Chemical and Clinical Research on Glycated Albumin

    OpenAIRE

    Ueda, Yuki; Matsumoto, Hideyuki

    2015-01-01

    The measuring method for glycated albumin (GA) has been developed as a new glycemic control marker since the beginning of the 21st century. Since GA has an advantage in reflecting glycemic status over a shorter period than hemoglobin A1c (HbA1c), much research and many reviews have been reported. However, so far there have been few reports on glycation sites based on the tertiary structure of human serum albumin (HSA) and the comparison of glycation rates between GA and HbA1c in detail. The p...

  13. Injury effects of advanced glycation end products on the cultured primary rat basal forebrain cholinergic neurons%糖基化终末产物对大鼠基底前脑胆碱能神经元的损伤作用

    Institute of Scientific and Technical Information of China (English)

    殷青青; 刘雪平; 董传芳; 董雪丽; 李艳菊; 罗鼎真; 侯训尧

    2012-01-01

    目的 研究糖基化终末产物(AGE-BSA)对原代培养的基底前脑胆碱能神经元形态、生存率、凋亡率、胆碱乙酰转移酶(ChAT)与乙酰胆碱酯酶(AchE)活性的影响.在体外水平研究AGEs在阿尔茨海默病(Alzheimer's disease,AD)神经元缺失发生中的作用及其可能机制.方法 原代培养大鼠基底前脑胆碱能神经元,观察细胞生长变化,进行免疫荧光细胞化学鉴定;用300 μg/mLAGE-BSA以及糖基化终末产物受体(RAGE)中和抗体阻断处理原代培养的基底前脑胆碱能神经元,作用不同时间后置于倒置显微镜下观察细胞形态变化;采用MTT法检测神经元的存活率;采用流式细胞术检测神经元的凋亡率;经比色法检测ChAT和AchE的活性变化.结果 AGEBSA干预胆碱能神经元72 h后,细胞形态发生明显损伤性变化,细胞存活率明显降低,凋亡率增高,ChAT活性明显下降,AchE活性明显升高;RAGE中和抗体阻断组72 h较之AGE-BSA组,细胞形态损伤变化较轻,生存率偏高,凋亡率较低,ChAT活性较高,AchE活性偏低,但比空白对照组生存率降低,凋亡率增高,ChAT活性明显下降,AchE活性明显升高.结论 糖基化终末产物作用72 h可以引起胆碱能神经元的损伤,并造成ChAT活性下降和AchE活性明显升高,部分阻断其与特异性受体RAGE的结合可以减弱其损伤作用,提示糖基化终末产物通过其受体参与了对胆碱能神经元的损伤作用.%Objective To investigate effects of advanced glycation end products (AGEs) on the cell morphology, survival rate, apoptosis rate, choline acetyltransfesterase (ChAT) activity and acetylcholine( AchE) activity of the cultured primary rat basal forebrain cholinergic neurons. To explore the effect and the possible mechanism of AGEs in Alzheimer's disease( AD) at the cell level. Methods Cultured primary rat basal forebrain cholinergic neurons were intervened by AGE-BSA and the RAGE neutralizing antibody, then the cell

  14. 糖基化终末产物促SH-SY5Y细胞β-淀粉样蛋白生成及相关机制%Effect of advanced glycation end products on expression of the β-amyloid protein in SH-SY5Y cells and its related mechanism

    Institute of Scientific and Technical Information of China (English)

    徐松; 高顺宗; 刘雪平; 王美霞; 董传芳; 侯亮; 袁树华

    2011-01-01

    目的 通过研究糖基化终末产物(AGEs-BSA)对培养的人神经母细胞瘤细胞(SH-SY5Y细胞)β-淀粉样蛋白(Aβ)的生成,以及淀粉样前体蛋白(APP)及相关酶-β-分泌酶(BACEl)、γ-分泌酶(PS1)的表达的影响,在体外水平探讨AGEs-BSA在阿尔茨海默病(AD)发病中的作用及其可能的机制.方法 以培养的SH-SY5Y细胞为模型,将细胞随机分为4组.用MTT实验得到的AGEs-BSA最佳干预时间及浓度干预细胞,用免疫细胞化学方法及ELISA方法观察及检测各组细胞内Aβ1-40、Aβ1-42表达,用免疫印迹法检测各组细胞内APP、BACE1、PS1变化.结果 BSA组与空白对照组相比APP、BACE1、PS1、Aβ的表达无明显差异(P>0.05);AGEs-BSA组与BSA组相比APP、BACE1、PS1、Aβ的表达明显增加(P<0.05);AGEs-BSA+抗RAGE中和抗体组APP、BACE1、PS1、Aβ的表达较单纯AGEs-BSA组明显减少(P<0.05),但仍高于BSA组(P<0.05).结论 糖基化终末产物能够促使SH-SY5Y细胞中APP的表达增加,并通过上调BACE1、PS1的活性使Aβ生成增加.通过阻断其与特异性受体RAGE的结合可以部分减少APP、BACE1,PS1及Aβ的表达和生成.%Objective To investigate the effect of advanced glycation end products (AGEs) on expressions of the β-amyloid protein (Aβ) and its related enzymes in cultured SH-SY5Y cells, and explore the effect and possible mechanism of AGEs on Alzheimer's disease(AD) the cell level.Methods Cultured SH-SY5Y cells were randomly divided into four groups: the blank control group, the AGE-modified bovine serum albumin (AGEs-BSA) group, the AGEs-BSA + anti-receptor for advanced glycation end products(RAGE) group and the BSA group.The MTT metabolic rate was employed to determine cells' growth and best concentration and time of the AGEs-BSA.Immunocytochemistry and ELISA were used to observe expressions of Aβ1-40 and Aβ1-42.Western blot was employed to examine changes of the amyloid precursor protein ( APP), β- secretion enzymel

  15. Advanced glycation end products in patients with peripheral artery disease

    OpenAIRE

    de Vos, Lisanne Carlijn

    2016-01-01

    Peripheral artery disease (PAD) is a disease in which stenosis or occlusion occurs of the arteries of the lower limbs. The most common underlying disease is atherosclerosis. The main presenting symptom of these patients is intermittent claudication, which is typical leg pain during walking that disappears during rest. Patients with progressed disease may suffer from rest pain, ulcers and are at risk for amputation. An estimated prevalence of the patients suffering from PAD is 200 million, whi...

  16. Advanced glycation end products in patients with peripheral artery disease

    NARCIS (Netherlands)

    de Vos, Lisanne Carlijn

    2016-01-01

    Peripheral artery disease (PAD) is a disease in which stenosis or occlusion occurs of the arteries of the lower limbs. The most common underlying disease is atherosclerosis. The main presenting symptom of these patients is intermittent claudication, which is typical leg pain during walking that disa

  17. Effect of some high consumption spices on hemoglobin glycation

    OpenAIRE

    Naderi, G. H.; Narges J Dinani; S Asgary; M Taher; Nikkhoo, N.; Boshtam, M.

    2014-01-01

    Formation of glycation products is major factor responsible in complications of diabetes. Worldwide trend is toward the use of natural additives in reducing the complications of diseases. Therefore, there is a growing interest in natural antiglycation found in plants. Herbs and spices are one of the most important targets to search for natural antiglycation from the point of view of safety. This study investigated the ability of some of the spices to inhibit glycation process in a hemoglobin/...

  18. Productos finales de la glicación y de la lipoxidación como amplificadores de la inflamación: papel de los alimentos Advanced glycation and lipoxidation end products-amplifiers of inflammation: the role of food

    Directory of Open Access Journals (Sweden)

    S. Bengmark

    2007-12-01

    associated with changes in lifestyle habits, including those related to the consumption of processed foodstuffs. In these foods advanced glycation end products (AGE and advanced lipoperoxydation products (ALE are formed as a consequence of the reactivity of proteins, carbohydrates, lipid and other components. The aim of the present review is to offer a perspective of how AGE and ALE affect the physiology and development of CD. Continous intake of AGE and ALE contributes to the exccesive accumulation of these products into body tissues, which in turn negatively influence the innate immune system, inflammatory responses, and resistance to diseases. This is achieved by direct interaction of AGE and ALE with specific cell AGE receptors (RAGE that have a key role as master switches regulating the development of CD. Long-life molecules, namely collagen and myelin, and low-turnover tissues, e.g. connective, bone and neural tissues, are the main targets of AGE and ALE. In these tissues, AGE and ALE lead to the synthesis of insoluble compounds that severely alter cellular functionality. It has been reported associations of AGE and ALE with allergic and autoimmune diseases, Alzheimer disease and other degenerative disorders, catarats, atherosclerosis, cancer, and diabetes mellitus type 2, as well as a number of endocrine, gastrointestinal, skeleton-muscle, and urogenital alterations. Controlling all those pathologies would need further dietary recommendations aiming to limit the intake of processed foods rich in AGE and ALE, as well as to reduce the formation of those products by improving technological processes applicable to foods.

  19. Glycated hemoglobin in camel: Minimal correlation with blood glucose level

    Directory of Open Access Journals (Sweden)

    Bazzi Mohammad D.

    2013-01-01

    Full Text Available Glucose and glycated hemoglobin (Hb in the blood of camel (Camelus dromedarius and cow (Bos taurus were analyzed and compared with human values. Camel displayed high blood glucose concentration (9.7±2.8 mM but a low level of glycated-Hb (3.4± 0.23%.Cow blood samples did not show sufficient variations in glucose concentrations (5.7±0.73 mM or glycated Hb levels (3.2± 0.11% compared to human values. The low glycation of camel Hb at higher glucose concentrations suggest that certain factors protect the Hb from glycation at high glucose concentrations. Camel Hb also exhibited a higher electrophoretic mobility than normal hemoglobin of human or cow. Camel Hb migrated at a rate corresponding to that of human Hb-C. Bioinformatics tools were used to explore the biochemical basis for the difference in camel Hb migratory position and its apparent resistance to glycation.

  20. Betanin reduces the accumulation and cross-links of collagen in high-fructose-fed rat heart through inhibiting non-enzymatic glycation.

    Science.gov (United States)

    Han, Junyan; Tan, Chang; Wang, Yiheng; Yang, Shaobin; Tan, Dehong

    2015-02-05

    We attempted to determine whether betanin (from natural pigments) that has antioxidant properties would be protective against fructose-induced diabetic cardiac fibrosis in Sprague-Dawley rats. Fructose water solution (30%) was accessed freely, and betanin (25 and 100 mg/kg/d) was administered by intra-gastric gavage continuously for 60 d. Rats were sacrificed after overnight fast. The rat blood and left ventricle were collected. In vitro antiglycation assay in bovine serum albumin/fructose system was also performed. In rats treated only with fructose, levels of plasma markers: glucose, insulin, HOMA and glycated hemoglobin rised, left ventricle collagen accumulated and cross-linked, profibrotic factor-transforming growth factor (TGF)-β1 and connective tissue growth factor (CTGF) protein expression increased, and soluble collagen decreased, compared with those in normal rats, showing fructose induces diabetic cardiac fibrosis. Treatment with betanin antagonized the changes of these parameters, demonstrating the antifibrotic role of betanin in the selected diabetic models. In further mechanistic study, betanin decreased protein glycation indicated by the decreased levels of protein glycation reactive intermediate (methylglyoxal), advanced glycation end product (N(ε)-(carboxymethyl) lysine) and receptors for advanced glycation end products (AGEs), antagonized oxidative stress and nuclear factor-κB activation elicited by fructose feeding, suggesting inhibition of glycation, oxidative stress and nuclear factor-κB activation may be involved in the antifibrotic mechanisms. Betanin also showed anitglycative effect in BSA/fructose system, which supported that anitglycation was involved in betanin's protective roles in vivo. Taken together, the potential for using betanin as an auxillary therapy for diabetic cardiomyopathy deserves to be explored further.

  1. AGEs对兔软骨细胞TNF-α和MMP-13表达的影响及其机制研究%The effects of advanced glycation end products on expression of tumor necrosis factor-αand matrix metalloproteinase-13 in rabbit chondrocytes and its mechanism

    Institute of Scientific and Technical Information of China (English)

    陈铖; 马翅; 张莹; 肖钧; 蔡巍; 谭海涛

    2013-01-01

    目的:探讨晚期糖基化终末产物(AGEs)对兔软骨细胞肿瘤坏死因子-α(TNF-α)和基质金属蛋白酶-13(MMP-13)的影响及可能机制。方法:不同浓度的AGEs与兔软骨细胞共孵育48h后采用RT-PCR方法检测TNF-α和MMP-13的mRNA表达量,试剂盒方法检测过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性及丙二醛(MDA)水平,荧光探针法检测细胞内活性氧(ROS)水平。AGEs与兔软骨细胞共孵育的同时,分别加入AGEs受体的抗体(Anti-RAGE)及核因子-κB(NF-κB)的特异性阻断剂PDTC处理,同法检测TNF-α和MMP-13的mRNA表达量。结果:与AGEs共孵育48h后兔软骨细胞TNF-α及MMP-13表达明显增多,CAT、SOD活性降低,MDA、ROS含量增多,均呈浓度依赖性;分别加入Anti-RAGE 及PDTC 处理后软骨细胞TNF-α及MMP-13表达明显低于AGEs单独处理组(P0.05)。结论:AGEs能诱导软骨细胞TNF-α和MMP-13表达增多,其机制与激活RAGE,诱导ROS生成增多,激活NF-κB信号通路有关。%Objective To detect the effects of advanced glycation end products (AGEs) on expression of tu-mor necrosis factor-α(TNF-α) and matrix metalloproteinase-13(MMP-13) in rabbit chondrocytes and its mecha-nism. Methods The chondrocytes were incubated with different concentrations of AGEs for 48h, the expression of TNF-αand MMP-13 mRNA were detected by reverse transcription polymerase chain reaction(RT-PCR),the lev-el of catalase (CAT), Malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) were detected by kits, and the level of ROS is measured by the method of Fluorescent probe. The effect of anti-RAGE(Receptor for AGEs) and PDTC(the inhibitor of NF-KB) on the expression of TNF-αand MMP-13 induced by AGEs were also measured by RT-PCR. Results After chondrocytes were incubated with AGEs, dose-dependly increased the ex-pression of TNF-αand MMP-13 (P0.05). Conclusion AGEs can induce the TNF-αand MMP-13 expression. It's mechanism may

  2. 糖基化终末产物对脂多糖介导下人牙周膜干细胞增殖和骨向分化能力的影响%Effect of advanced glycation end products on proliferation and osteogenic differentiation of lipopolysaccharide-stimulated human periodontal ligament stem cells

    Institute of Scientific and Technical Information of China (English)

    王岚; 夏佳佳; 邓超; 伍燕; 刘琪; 金岩

    2011-01-01

    AIM : To investigate the effect of advanced glycation end products ( AGEs) on proliferation and osteogenic differentiation of lipopolysaccharide ( LPS)-stimulated human periodontal ligament stem cells ( HPDLSCs).METHODS : The effects of LPS and AGEs on the proliferation of HPDLSCs were analyzed by MTT assay.The expressions of interleukin-6 ( IL-6 ) , alkaline phosphatase ( ALP) and Runt-related transcription factor-2 ( RUNX-2) mRNA of HPDLSCs which were stimulated by LPS ( 1O μg/mL) and AGEs (100 μg/mL) were detected by RT-PCR.RESULTS : MIT assay showed that LPS and AGEs inhibited the proliferation of HPDLSCs in a dose dependent manner.LPS stimulation significantly increased IL - 6 expression and inhibited ALP and RUNX-2 expression in HPDLSCs.Co -stimulation of HPDLSCs with LPS and ACEs markedly enhanced the effects of LPS on IL-6, ALP and RUNX -2 expression.CONCLUSION : LPS and ACEs inhibited the proliferation of HPDLSCs in a concentration-dependent manner.AGEs can enhance the stimulatory effects of LPS in up - regulating IL-6 expression and the inhibitory effects of LPS in down-regulating osteogenic factors expression.Our results suggest that diabetes may increase the degree of periodontal inflammation in patients with periodontitis.%目的:探讨糖基化终末产物(AGEs)对脂多糖(LPS)介导下的人牙周膜干细胞(HPDLSCs)增殖和骨向分化能力的影响.方法:HPDLSCs培养和鉴定;MTT法检测不同浓度LPS和AGEs对HPDLSCs增殖能力的影响;Real Time-PCR检测10μg/mL LPS和100μg/mL LAGE刺激HPDLSCs后白细胞介素-6(IL-6)、碱性磷酸酶(ALP)和Runt-related transcription factor2(RUNX-2)mRNA的表达水平.结果:与正常组比较,10、100μg/mL LPS均抑制HPDLSCs的增殖,50、100、200 μg/mL AGEs均抑制HPDLSCs的增殖,100、200