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Rationale: Soluble RAGE (sRAGE) is a promising biomarker for COPD and an attractive target for biomarker validation studies. Validated, reliable and clinically applicable biomarkers are needed for the early detection of COPD, identification of clinically relevant subgroups of COPD and for the selection of subjects for clinical trials. The circulating levels of sRAGE are decreased in COPD patients compared to both smoking and non-smoking controls, and are even further decreased during COPD exacerbations. Furthermore, the serum levels of sRAGE associate with neutrophilic airway inflammation, decline in FEV1, and emphysema. Methods: To date, most studies use commercially available ELISA kits for measurements of sRAGE, which have limited accuracy and reproducibility. Here, we present two novel liquid chromatography-mass spectrometry (LC-MS) methods for the quantification of sRAGE in serum. Our first approach measures the free, unbound fraction of sRAGE using an immunoaffinity enrichment-based method as sample preparation, comparable to the ELISA. Our second approach is an antibody-free method based on strong cation exchange solid-phase extraction, which likely measures the total sRAGE fraction. Both sample preparation methods are followed by LC-MS analysis in the multiple reaction monitoring mode. Results: Using the immunoaffinity enrichment-based method we are able to detect and quantify sRAGE in human serum over a large range (0.1-10 ng/mL) with high precision and accuracy (CV

Rationale: Soluble RAGE (sRAGE) is a promising biomarker for COPD and an attractive target for biomarker validation studies. Validated, reliable and clinically applicable biomarkers are needed for the early detection of COPD, identification of clinically relevant subgroups of COPD and for the selection of subjects for clinical trials. The circulating levels of sRAGE are decreased in COPD patients compared to both smoking and non-smoking controls, and are even further decreased during COPD exacerbations. Furthermore, the serum levels of sRAGE associate with neutrophilic airway inflammation, decline in FEV1, and emphysema. Methods: To date, most studies use commercially available ELISA kits for measurements of sRAGE, which have limited accuracy and reproducibility. Here, we present two novel liquid chromatography-mass spectrometry (LC-MS) methods for the quantification of sRAGE in serum. Our first approach measures the free, unbound fraction of sRAGE using an immunoaffinity enrichment-based method as sample preparation, comparable to the ELISA. Our second approach is an antibody-free method based on strong cation exchange solid-phase extraction, which likely measures the total sRAGE fraction. Both sample preparation methods are followed by LC-MS analysis in the multiple reaction monitoring mode. Results: Using the immunoaffinity enrichment-based method we are able to detect and quantify sRAGE in human serum over a large range (0.1-10 ng/mL) with high precision and accuracy (CV

Purpose of review: Sepsis is still associated with excess morbidity and mortality worldwide, despite significant advances in critical care medicine. A novel approach is needed in the treatment of sepsis, one that will aim to correct the specific immunologic imbalance that is detrimental to the septic host. Recent findings: As receptor for advanced glycation end products (RAGE) is involved in diverse cellular mechanisms that to a lesser or greater extent participate in the septic process, modulating its function could favorably affect outcome. Altering RAGE may result in regulating the release of proinflammatory cytokines, controlling apoptosis or modifying endothelial architecture. In that regard, several strategies have been used to study RAGE deficiency in experimental models of sepsis including antibodies against RAGE, genetically deleted RAGE knockouts, siRNA to silence RAGE, soluble forms of RAGE, and antibodies and inhibitors directed toward RAGE ligands, such as HMGB1 and S100 proteins. Summary: These studies thus far have yielded inconsistent results as to whether RAGE is beneficial or not to the host response during bacterial infection and sepsis. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins. 25 3 304 311

Objectives Levels of soluble receptor for advanced glycation endproducts (sRAGE) have been linked to several components of the metabolic syndrome. We tested the hypothesis that plasma levels of sRAGE may be associated with non-alcoholic fatty liver disease. Design and methods We enrolled subjects with definite nonalcoholic steatohepatitis (NASH, n = 40), borderline NASH (n = 8), simple fatty liver (n = 9) and healthy controls (n = 14). Plasma levels of sRAGE were measured by ELISA. Results Concentrations of sRAGE were significantly lower in patients with definite NASH (1080 ± 392 pg/mL, P

Altered vascular reactivity due to endothelial dysfunction, consequent to vascular damage, is observed in rheumatoid arthritis. We investigated the effect of angiotensin (Ang)-(1-7) on vasculature changes in arthritis induced by complete Freund's adjuvant in male Wistar rats. Arthritis decreased soluble receptor for advanced glycation end products (sRAGE) whereas elevated aortic RAGE expression, increased interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), systolic blood pressure and the contractility induced by phenylephrine and KCl. Moreover, arthritis decreased the relaxing effect of acetylcholine. Neither arthritis nor Ang-(1-7) altered sodium nitroprusside relaxation. Ang-(1-7) reversed the effect of arthritis on TNF-α, sRAGE and RAGE expression without any effect on the IL-1β. Ang-(1-7) decreased phenylephrine and KCl contractility, especially in the endothelial-denuded aorta, whereas increased acetylcholine relaxation in the endothelial-intact aorta. Ang-(1-7) could find its place in the treatment protocol of arthritis and vascular diseases. © 2016 S. Karger AG, Basel.

Altered vascular reactivity due to endothelial dysfunction, consequent to vascular damage, is observed in rheumatoid arthritis. We investigated the effect of angiotensin (Ang)-(1-7) on vasculature changes in arthritis induced by complete Freund's adjuvant in male Wistar rats. Arthritis decreased soluble receptor for advanced glycation end products (sRAGE) whereas elevated aortic RAGE expression, increased interleukin-1ß (IL-1ß) and tumor necrosis factor-? (TNF-?), systolic blood pressure and the contractility induced by phenylephrine and KCl. Moreover, arthritis decreased the relaxing effect of acetylcholine. Neither arthritis nor Ang-(1-7) altered sodium nitroprusside relaxation. Ang-(1-7) reversed the effect of arthritis on TNF-?, sRAGE and RAGE expression without any effect on the IL-1ß. Ang-(1-7) decreased phenylephrine and KCl contractility, especially in the endothelial-denuded aorta, whereas increased acetylcholine relaxation in the endothelial-intact aorta. Ang-(1-7) could find its place in the treatment protocol of arthritis and vascular diseases. © 2016 S. Karger AG, Basel.

Apoptotic cells trigger immune tolerance in engulfing phagocytes. This poorly understood process is believed to contribute to the severe immunosuppression and increased susceptibility to nosocomial infections observed in critically ill sepsis patients. Extracellular high mobility group box 1 (HMGB1) is an important mediator of both sepsis lethality and the induction of immune tolerance by apoptotic cells. We have found that HMGB1 is sensitive to processing by caspase-1, resulting in the production of a fragment within its N-terminal DNA-binding domain (the A-box) that signals through the receptor for advanced glycation end products (RAGE) to reverse apoptosis-induced tolerance. In a two-hit mouse model of sepsis, we show that tolerance to a secondary infection and its associated mortality were effectively reversed by active immunization with dendritic cells treated with HMGB1 or the Abox fragment, but not a noncleavable form of HMGB1. These findings represent a novel link between caspase-1 and HMGB1, with potential therapeutic implications in infectious and inflammatory diseases. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

With the continuing epidemics of obesity and diabetes, nonalcoholic fatty liver disease (NAFLD) has received increased attention. Great efforts are being undertaken to improve the noninvasive diagnosis of NAFLD, with the ultimate goal of optimizing treatment options and clinical outcomes. Research suggests that blood-borne biochemical markers can be used to distinguish simple steatosis from nonalcoholic steatohepatitis (NASH), thus reducing the need of liver biopsy. Future developments in the field of diagnostic biochemistry within the spectrum of NAFLD can make this approach ideal for screening and monitoring purposes. In this review, we provide an overview of the different blood-borne markers which have been recently proposed for differentiating simple steatosis from NASH. We will also consider the practical and statistical issues that seem to be limiting the effective integration of biomarkers into clinical development.

Currently the treatment mainstay of sepsis is early and appropriate antibiotic therapy, accompanied by aggressive fluid administration, the use of vasopressors when needed and the prompt initiation of measures to support each failing organ. Activated protein C and hydrocortisone, when used accordingly can affect mortality. As the pathophysiologic events that take place during sepsis are being elucidated, new molecules that target each step of those pathways are being tested. However, a lot of those molecules affect various mediators of the sepsis cascade including inflammatory cytokines, cellular receptors, nuclear transcription factors, coagulation activators and apoptosis regulators. Over the last decade, a multitude of clinical trials and animal studies have investigated strategies that aimed to restore immune homeostasis either by reducing inflammation or by stimulating the innate and adaptive immune responses. Antibiotics, statins and other molecules with multipotent immunomodulatory actions have also been studied in the treatment of sepsis. © 2011 Expert Reviews Ltd. 9 11 1013 1033

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 < .001) group had a significant increase from baseline in sRAGE values that was not seen in the medical nutrition therapy and rosiglitazone groups. We conclude that, in type 2 diabetes mellitus patients, pioglitazone—but not rosiglitazone—significantly raised sRAGE, which may contribute to its antiatherogenic effects.

Ligands for the receptor for advanced glycation endproducts (RAGE) are increased in RA synovial fluid (SF), serum and synovium. Since RAGE is present on fibroblast-like synoviocytes (FLS), the present study investigates whether the RAGE ligands HMGB-1 and AGEs are able to stimulate the characteristic, pathological invasive behaviour of these cells. FLS were obtained during joint replacement surgery. FLS were seeded in serum free medium with HMGB-1 or glycated albumin (BSA-AGE) on transwell filters coated with Matrigel. The lower compartment contained medium with serum as a chemoattractant. After three days, the percentage of invading cells was determined and compared to the control invasion. Stimulation with HMGB-1 increased invasiveness to 125% compared to the control (p = 0.001). Addition of anti-RAGE antibody reduced this back to baseline (98%, p = 0.002). Stimulation with BSA-AGE, another RAGE ligand, increased invasiveness to 150% compared to the control (p = 0.003). Addition of anti RAGE was again able to reduce the increased invasiveness back to baseline (95%, p = 0.008). HMGB-1 and BSA-AGE stimulated the invasiveness of RA-FLS by activation of RAGE. As such, RAGE may be an interesting target for therapy directed at the inhibition of synoviocyte activation. © Copyright Clinical and Experimental Rheumatology 2007.

Accumulation of advanced glycation endproducts (AGEs) plays a crucial part in the development of age-related diseases and diabetic complications. AGEs are formed in vivo via the so-called Maillard reaction: a reducing sugar reacts with a protein to form a labile Amadori product that is subsequently stabilized, producing an irreversible, non-enzymatic post-translational modification of the protein involved. Recently, it has become clear that, in addition to sugars, lipids play an important role in the initiation of AGE formation, and that genetic factors contribute to an individual's AGE levels. The highest AGE levels are found in tissues with slow turnover, such as tendon, skin, bone, amyloid plaques and cartilage. AGEs exert their effects by adversely affecting the mechanical properties of the matrix and by modulating tissue turnover. In cartilage, these detrimental effects result in tissue that is more prone to the development of osteoarthritis. As such, the accumulation of AGEs provides the first molecular mechanism explaining the age-related increase in the incidence of osteoarthritis. Ongoing research into anti-AGE-ing therapies, such as pyrodoxamine and thiazolium compounds, which are often developed to prevent AGE-induced diabetic complications, might also prove beneficial for the prevention of osteoarthritis. © Elsevier Ltd. All rights reserved. Chemicals / CAS: advanced glycation end product receptor, 198785-73-8, 247590-69-8; alagebrium, 341028-37-3; glucosamine, 3416-24-8, 4607-22-1; lipid, 66455-18-3; pyridoxamine, 13876-70-5, 5103-96-8, 524-36-7, 85-87-0; Glycosylation End Products, Advanced

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. Using standardized procedures and a variety of AGE measures, the present study aimed to characterize the AGEs that bind to RAGE and their formation kinetics in vitro. To produce AGEs with varying RAGE binding affinity, bovine serum albumin (BSA) AGEs were prepared with 0.5M glucose, fructose, or ribose at times of incubation from 0 to 12 weeks or for up to 3 days with glycolaldehyde or glyoxylic acid. The AGE-BSAs were characterized for RAGE binding affinity, fluorescence, absorbance, carbonyl content, reactive free amine content, molecular weight, pentosidine content, and N-ε-carboxymethyl lysine content. Ribose-AGEs bound RAGE with high affinity within 1 week of incubation in contrast to glucose- and fructose-AGE, which required 12 and 6 weeks, respectively, to generate equivalent RAGE ligands (IC50=0.66, 0.93, and 1.7μM, respectively). Over time, all of the measured AGE characteristics increased. However, only free amine content robustly correlated with RAGE binding affinity. In addition, detailed protocols for the generation of AGEs that reproducibly bind RAGE with high affinity were developed, which will allow for further study of the RAGE-AGE interaction. © 2003 Elsevier Inc. All rights reserved. Chemicals / CAS: advanced glycation end product receptor, 198785-73-8, 247590-69-8; fructose, 30237-26-4, 57-48-7, 7660-25-5, 77907-44-9; glucose, 50-99-7, 84778-64-3; glyoxylic acid, 298-12-4; pentosidine, 124505-87-9; ribose, 34466-20-1, 50-69-1, 93781-19-2; Acetaldehyde, 75-07-0; advanced glycosylation end-product receptor; Amines; Arginine, 74-79-3; Fructose, 30237-26-4; Glucose, 50-99-7; glycolaldehyde, 141-46-8; Glycosylation End Products, Advanced; Glyoxylates; glyoxylic acid, 298-12-4; Ligands; Lysine, 56-87-1; Membrane Proteins; N(6)-carboxymethyllysine, 5746-04-3; pentosidine, 124505-87-9; Receptors, Immunologic; Recombinant Proteins; Ribose, 50-69-1; Serum Albumin, Bovine Molecular Sequence Numbers: GENBANK: CAA76847

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. Using standardized procedures and a variety of AGE measures, the present study aimed to characterize the AGEs that bind to RAGE and their formation kinetics in vitro. To produce AGEs with varying RAGE binding affinity, bovine serum albumin (BSA) AGEs were prepared with 0.5M glucose, fructose, or ribose at times of incubation from 0 to 12 weeks or for up to 3 days with glycolaldehyde or glyoxylic acid. The AGE-BSAs were characterized for RAGE binding affinity, fluorescence, absorbance, carbonyl content, reactive free amine content, molecular weight, pentosidine content, and N-ε-carboxymethyl lysine content. Ribose-AGEs bound RAGE with high affinity within 1 week of incubation in contrast to glucose- and fructose-AGE, which required 12 and 6 weeks, respectively, to generate equivalent RAGE ligands (IC50=0.66, 0.93, and 1.7μM, respectively). Over time, all of the measured AGE characteristics increased. However, only free amine content robustly correlated with RAGE binding affinity. In addition, detailed protocols for the generation of AGEs that reproducibly bind RAGE with high affinity were developed, which will allow for further study of the RAGE-AGE interaction. © 2003 Elsevier Inc. All rights reserved. Chemicals / CAS: advanced glycation end product receptor, 198785-73-8, 247590-69-8; fructose, 30237-26-4, 57-48-7, 7660-25-5, 77907-44-9; glucose, 50-99-7, 84778-64-3; glyoxylic acid, 298-12-4; pentosidine, 124505-87-9; ribose, 34466-20-1, 50-69-1, 93781-19-2; Acetaldehyde, 75-07-0; advanced glycosylation end-product receptor; Amines; Arginine, 74-79-3; Fructose, 30237-26-4; Glucose, 50-99-7; glycolaldehyde, 141-46-8; Glycosylation End Products, Advanced; Glyoxylates; glyoxylic acid, 298-12-4; Ligands; Lysine, 56-87-1; Membrane Proteins; N(6)-carboxymethyllysine, 5746-04-3; pentosidine, 124505-87-9; Receptors, Immunologic; Recombinant Proteins; Ribose, 50-69-1; Serum Albumin, Bovine Molecular Sequence Numbers: GENBANK: CAA76847

Accumulation of advanced glycation endproducts (AGEs) plays a crucial part in the development of age-related diseases and diabetic complications. AGEs are formed in vivo via the so-called Maillard reaction: a reducing sugar reacts with a protein to form a labile Amadori product that is subsequently stabilized, producing an irreversible, non-enzymatic post-translational modification of the protein involved. Recently, it has become clear that, in addition to sugars, lipids play an important role in the initiation of AGE formation, and that genetic factors contribute to an individual's AGE levels. The highest AGE levels are found in tissues with slow turnover, such as tendon, skin, bone, amyloid plaques and cartilage. AGEs exert their effects by adversely affecting the mechanical properties of the matrix and by modulating tissue turnover. In cartilage, these detrimental effects result in tissue that is more prone to the development of osteoarthritis. As such, the accumulation of AGEs provides the first molecular mechanism explaining the age-related increase in the incidence of osteoarthritis. Ongoing research into anti-AGE-ing therapies, such as pyrodoxamine and thiazolium compounds, which are often developed to prevent AGE-induced diabetic complications, might also prove beneficial for the prevention of osteoarthritis. © Elsevier Ltd. All rights reserved. Chemicals / CAS: advanced glycation end product receptor, 198785-73-8, 247590-69-8; alagebrium, 341028-37-3; glucosamine, 3416-24-8, 4607-22-1; lipid, 66455-18-3; pyridoxamine, 13876-70-5, 5103-96-8, 524-36-7, 85-87-0; Glycosylation End Products, Advanced

Ligands for the receptor for advanced glycation endproducts (RAGE) are increased in RA synovial fluid (SF), serum and synovium. Since RAGE is present on fibroblast-like synoviocytes (FLS), the present study investigates whether the RAGE ligands HMGB-1 and AGEs are able to stimulate the characteristic, pathological invasive behaviour of these cells. FLS were obtained during joint replacement surgery. FLS were seeded in serum free medium with HMGB-1 or glycated albumin (BSA-AGE) on transwell filters coated with Matrigel. The lower compartment contained medium with serum as a chemoattractant. After three days, the percentage of invading cells was determined and compared to the control invasion. Stimulation with HMGB-1 increased invasiveness to 125% compared to the control (p = 0.001). Addition of anti-RAGE antibody reduced this back to baseline (98%, p = 0.002). Stimulation with BSA-AGE, another RAGE ligand, increased invasiveness to 150% compared to the control (p = 0.003). Addition of anti RAGE was again able to reduce the increased invasiveness back to baseline (95%, p = 0.008). HMGB-1 and BSA-AGE stimulated the invasiveness of RA-FLS by activation of RAGE. As such, RAGE may be an interesting target for therapy directed at the inhibition of synoviocyte activation. © Copyright Clinical and Experimental Rheumatology 2007.

Diabetes represents an independent risk factor for coronary artery disease (CAD), and the prognosis in terms of survival rates is worse for diabetic patients who have CAD with respect to those with CAD but no diabetes. An acute coronary event represents a cause of death in more than 30% of diabetics. Experimental studies suggested that the increased incidence of myocardial infarction in diabetics is due to an increased risk of developing atherosclerotic plaque with subsequent ulceration and intracoronary thrombus formation. Structural abnormalities of the coronary vessel wall were associated with an abnormal pattern of coronary flow and of coagulation abnormalities: all these abnormalities explain the epidemiological evidence of widespread and severe vascular atherosclerotic disease in diabetics. Due to the extreme complexity of ischemic vascular disease in patients with diabetes, an optimal therapeutic strategy is based on the correction of elevated blood glucose and lipid levels, of blood pressure, of platelet and coagulation abnormalities and of any other risk factor. Both percutaneous and surgical myocardial revascularization have been proved equally effective for CAD treatment in diabetes, even though a recent randomized trial has shown a significantly improved outcome after surgical revascularization. More recently the characterization of the advanced glycation end-product receptor opened new perspectives in the treatment of the complications of diabetes, and gave a new impact to the need of further investigations, through new randomized trials, of the best therapeutic options for diabetic patients.