Soluble RAGE Research Articles

The effects of acute hypoxia on tissue oxygenation and circulating alarmins in healthy adults.

The binding of high-mobility group box-1 (HMGB-1) to the membrane receptor for advanced glycation end-products (mRAGE) is a key early mediator of non-infectious inflammation and its triggers include ischaemia/hypoxia. The effects of acute hypoxia on soluble RAGE (sRAGE) are unknown. Fourteen healthy adults (50 % women; 26.6+/-3.8 years) were assessed at baseline normoxia (T0), followed by four time-points (T90, 95, 100 and 180 min) over three hours of continuous normobaric hypoxia (NH, 4,450 m equivalent) and again 60 min after return to normoxia (T240). A 5-min exercise step test was performed during NH at T90. Plasma concentrations of HMGB-1, sRAGE VCAM-1, ICAM-1, VEGF IL-8 and IL-13 were measured using venous blood. Arterial and tissue oxygen saturations were measured using pulse oximetry (SpO(2)) and near-infrared spectroscopy (StO(2)), respectively. NH led to a significant reduction in SpO(2), StO(2), sRAGE and VEGF, which was compounded by exercise, before increasing to baseline values with normoxic restoration (T240). NH-exercise led to a paired increase in HMGB-1. sRAGE inversely correlated with HMGB-1 (r=-0.32; p=0.006), heart rate (r=-0.43; p=0.004) but was not linked to SpO(2) or StO(2). In conclusion, short-term NH leads to a fall in sRAGE and VEGF concentrations with a transient rise post NH-exercise in HMGB-1.

G82S polymorphism of receptor for advanced glycation end products gene and serum soluble RAGE levels in mild cognitive impairment and dementia of Alzheimer's type patients in Turkish population

Alzheimer’s disease (AD) is a chronic, neurodegenaration resulting in progressive cognitive decline leading to dementia. Mild cognitive impairment (MCI) is also a clinical definition of cognitive decline without functional impairment. Receptor for advanced glycation end products (RAGE) is one of the neuronal membrane receptors that binds amyloid beta peptide (Aβ) triggering Aβ-related pathologic signalling mechanisms. Soluble RAGE (sRAGE) is the soluble isoform of RAGE and it collects peripheral Aβ by acting as a sink, prevents both RAGE-AGE interaction and transfer of Aβ into brain.In this study, an association was investigated in Turkish cohorts of patients with dementia with Alzheimer's Type (DAT) and MCI patients by measuring serum sRAGE levels and by genotyping G82S polymorphism and comparing them to healthy control (HC) subjects.Although the serum sRAGE levels showed a decreasing manner among the groups, these differences were not statistically significant (p = 0.2). This is the first study for Turkish population.

Role of Receptor for Advanced Glycation End Products in Regulating Lung Fluid Balance in Lipopolysaccharide-induced Acute Lung Injury and Infection-Related Acute Respiratory Distress Syndrome.

Receptor for advanced glycation end products (RAGE) is implicated in inflammatory responses in acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), but its role in pulmonary edema formation remains unclear, especially in infection-related ARDS mainly caused by pneumonia or sepsis. In this study, we investigated the role of RAGE in alveolar fluid regulation by using RAGE gene knockout (RAGE) mice in a murine ALI model induced by lipopolysaccharide (LPS), and by comparing soluble RAGE (sRAGE) levels in serum and bronchial alveolar lavage fluid between ARDS patients and control subjects. We found that RAGE knockout significantly improved alveolar fluid clearance and reduced pulmonary vascular albumin leakage upon LPS challenge. Furthermore, LPS-induced substantial decrease in lung expression of sodium-potassium ATPase (Na,K-ATPase), epithelial sodium channel, and zonula occluden-1 (ZO-1) were fully or partially restored by the deletion of RAGE. In addition to this, LPS-induced lung leukocyte infiltration and inflammatory cytokine and chemokine release were all attenuated in RAGE mice as compared to wide-type mice. In infection-related ARDS patients, both serum and bronchial alveolar lavage fluid levels of the sRAGE were much higher than those in control subjects, and they were positively correlated with pulmonary vascular permeability and levels of interleukin (IL)-6, IL-8, and macrophage inflammatory protein (MIP)-2. Taken together, we provided the first direct evidence for the essential role of RAGE in regulating lung fluid balance in infection-related ARDS/ALI. The underlying mechanisms may involve the downregulation of both ion-channel and tight junction proteins mediated by RAGE signaling in bacterial endotoxin-induced lung injury.

Clinical relevance of cleaved RAGE plasma levels as a biomarker of disease severity and functional outcome in aneurysmal subarachnoid hemorrhage

BackgroundCleaved receptor for advanced glycation end-products (cRAGE) has been introduced as a new inflammatory marker. We clarified the associations between cRAGE levels, disease severity and functional outcome in aneurysmal subarachnoid hemorrhage (aSAH). MethodsIn this prospective, observational study, plasma levels of total soluble RAGE (sRAGE) and endogenous secretory RAGE (esRAGE) were quantified in 108 aSAH patients and 108 controls. The level of cRAGE was calculated by subtracting the level of esRAGE from that of sRAGE. World Federation of Neurological Surgeons (WFNS) score, modified Fisher score, and Hunt Hess (HH) score were recorded to assess aSAH severity. Relationship between plasma cRAGE levels and 6-month poor outcome (Glasgow Outcome Scale score of 1–3) was assess using multivariate analysis. ResultsPlasma cRAGE levels were significantly higher in patients than in controls. Its levels were significantly correlated with WNFS score, modified Fisher score and HH score of patients. Plasma cRAGE emerged as an independent predictor for 6-month poor outcome. Area under receiver operating characteristic curve (AUC) of this biomarker was similar to those of WNFS score, modified Fisher score and HH score. Moreover, it significantly improved AUCs of WNFS score, modified Fisher score and HH score. ConclusionsPlasma cRAGE levels are highly associated with the severity and poor prognosis in aSAH.

A Longitudinal Study of Alterations of S100B, sRAGE and Fas Ligand in Association to Olanzapine Medication in a Sample of First Episode Patients with Schizophrenia.

Neuroinflammation has been proposed as a major mechanism in schizophrenic disorder. Specifically, an increase in the inflammatory response in the central nervous system is capable of activating microglial cells, leading to the release of pro-inflammatory cytokines and thus activating apoptotic signaling. An increase in apoptosis may underlie a potential role of immune neuropathology in the etiopathogenesis of schizophrenia and specifically, the onset of the disorder. We analyzed in whole blood, levels of S100B, the receptor for advanced glycation end products (RAGE) and the apoptotic marker Fas Ligand in a sample of 13 first episode of schizophrenia twice at baseline before the initiation of any antipsychotic medication (A) and 6 weeks later following an antipsychotic monotherapy with olanzapine (B) and in a sample of 10 healthy controls. The S100B, RAGE and Fas Ligand showed statistically significant differences before and after treatment; the S100B measurements yielded a p-value of 0.004 while the soluble RAGE and Fas Ligand measurements yielded a p=0.03, and p=0.04 respectively. The differences between cases and controls were not statistically significant for all measurements, with the only exception being the S100B values where both samples A and B showed significantly higher values than the controls with p=8.5x10-8 and p=2.9x10-10 respectively. The levels of S100B, RAGE, and Fas Ligand of drug-naive first episode psychosis patients with schizophrenia were significantly higher than that of the same medicated first episode psychosis patients, indicating that an increase of apoptotic signaling is present at the onset of schizophrenia and is also associated with treatment progress.

Endogenous secretory RAGE increases with improvements in body composition and is associated with markers of adipocyte health

Background and aimsThe receptor for advanced glycation end products (RAGE) is implicated in obesogenesis. Conversely, soluble RAGE (sRAGE) competitively inhibits RAGE. Our aim was to determine the effects of weight-loss via alternate day fasting (ADF) on sRAGE isoforms and evaluate potential relationships with body composition. Methods and results42 obese participants were randomized to control (CON) or ADF. For 24 weeks, the ADF group consumed 25% or 125% of their caloric requirements on alternating days while the CON group did not change their diet. Body fat was measured via DXA, visceral fat (VAT) via MRI and subcutaneous fat (SAT) was derived by subtracting VAT from total fat. sRAGE isoforms were measured via ELISAs. After 24 weeks, ADF −6.8 (−9.5, −3.5)kg (Median, IQR) lost more weight than CON −0.3 (−1.9, 1.0)kg (p < 0.05). The change in endogenous secretory RAGE (esRAGE) was different between ADF 15 (−30, 78)pg/mL and CON −21 (−72, 16)pg/mL after 24 weeks (p < 0.05). To examine the effect of changes in body composition, the cohort was stratified by median weight-, fat-, SAT-, and VAT-loss. The changes in all sRAGE isoforms were different between those above and below median weight-loss (p < 0.05) with sRAGE isoforms tending to decrease in individuals below the median. Changes in total sRAGE and esRAGE were different between individuals above compared to below median fat- and SAT-loss (p < 0.05). Those above median fat-loss increased esRAGE by 29 (−5, 66)pg/mL (p < 0.05). ConclusionImprovements in body composition are related to increased sRAGE isoforms, implicating sRAGE as a potential target for the treatment of obesity. Clinical Trial RegistrationNCT00960505.

Effect of RAGE Manipulation on Diabetic Cardiomyopathy in Mice

Advanced glycation end-products (AGE) and their receptors (RAGE) have been implicated in the development of many ailments including diabetes. Soluble RAGE (sRAGE), which acts as a decoy of RAGE, has been studied as a potential therapeutic agent against vascular complications of diabetes. Here we tested the effects of RAGE manipulation in vivo on diabetic cardiomyopathy. We have reported that genetic over-expression of sRAGE produces a consistent high level of plasma sRAGE in mice. In this study, we created a mouse model that has over-expressed sRAGE with either intact or knocked-out RAGE. Diabetes was induced by STZ in following mice with: (1) over-expressed sRAGE and intact RAGE (S group); (2) over-expressed sRAGE and knocked-out RAGE (D group); and (3) wildtypes that have a normal expression of both sRAGE and RAGE (C group). During the 4-month of post-STZ injection, cardiovascular morphology and function were studied using serial Echocardiography, end-point invasive hemodynamic measurements and pathological analysis. A severe hyperglycemia was observed throughout the experiment in all diabetic mice. As expected, a significant reduction of bodyweight, heart weight, heart rate, left ventricular (LV) systolic parameters, LV diastolic parameters, LV Ejection fraction (EF), vascular functional parameters and survival rate (33%) were observed in C group, as indications of diabetic cardiomyopathy, compared to non-diabetic counterparts. Interestingly, in S group, those parameters were identical to that in C group (30% of survival rate in S group). However, in D group, while the effects of hyperglycemia on bodyweight and LV diastolic parameters were similar to that in C and S groups, there was a significantly better survival rate (70%; p<0.05), better LV systolic parameters, better EF and better vascular functional parameters, and lesser reduction in heart weight and heart rate compared to that in C and S groups (Figure). Our results suggested that manipulation of RAGE signaling attenuates the development of diabetic cardiomyopathy. Advanced glycation end-products (AGE) and their receptors (RAGE) have been implicated in the development of many ailments including diabetes. Soluble RAGE (sRAGE), which acts as a decoy of RAGE, has been studied as a potential therapeutic agent against vascular complications of diabetes. Here we tested the effects of RAGE manipulation in vivo on diabetic cardiomyopathy. We have reported that genetic over-expression of sRAGE produces a consistent high level of plasma sRAGE in mice. In this study, we created a mouse model that has over-expressed sRAGE with either intact or knocked-out RAGE. Diabetes was induced by STZ in following mice with: (1) over-expressed sRAGE and intact RAGE (S group); (2) over-expressed sRAGE and knocked-out RAGE (D group); and (3) wildtypes that have a normal expression of both sRAGE and RAGE (C group). During the 4-month of post-STZ injection, cardiovascular morphology and function were studied using serial Echocardiography, end-point invasive hemodynamic measurements and pathological analysis. A severe hyperglycemia was observed throughout the experiment in all diabetic mice. As expected, a significant reduction of bodyweight, heart weight, heart rate, left ventricular (LV) systolic parameters, LV diastolic parameters, LV Ejection fraction (EF), vascular functional parameters and survival rate (33%) were observed in C group, as indications of diabetic cardiomyopathy, compared to non-diabetic counterparts. Interestingly, in S group, those parameters were identical to that in C group (30% of survival rate in S group). However, in D group, while the effects of hyperglycemia on bodyweight and LV diastolic parameters were similar to that in C and S groups, there was a significantly better survival rate (70%; p<0.05), better LV systolic parameters, better EF and better vascular functional parameters, and lesser reduction in heart weight and heart rate compared to that in C and S groups (Figure). Our results suggested that manipulation of RAGE signaling attenuates the development of diabetic cardiomyopathy.

Soluble RAGE Sequesters Advanced Glycation End Products following an Overnight Fast in T1DM Patients

Context and Objectives: Advanced glycation end products (AGEs) promote the development of diabetic complications through activation of their receptor (RAGE). Isoforms of soluble RAGE (sRAGE) sequester AGEs and thus protect against RAGE-mediated diabetic complications. Low cellular energy, such as during fasting, activates sRAGE production. We investigated the effect of an overnight fast on circulating substrates, hormones, AGEs, and sRAGE isoforms in 26 individuals with type 1 diabetes (T1DM). Participants and Methods: Blood was collected from young (18-30 years) T1DM patients on insulin pumps before and after an overnight fast. Circulating AGEs were measured via LC-MS/MS and sRAGE isoforms were analyzed via ELISA. eGFRcystatin-c was calculated based on circulating cystatin-c measured via ELISA. Results: Glucose, insulin, glucagon, and eGFRcystatin-c decreased while cortisol increased following the overnight fast (p&amp;lt;0.05). NEFAs and cholesterol did not change (p&amp;gt;0.05). AGEs (CML, CEL, 3DG-H, MG-H1, and G-H1) decreased (21-58%, p&amp;lt;0.0001) while total sRAGE, cleaved RAGE (cRAGE), and endogenous secretory RAGE (esRAGE) increased (22-24%, p&amp;lt;0.0001) following the overnight fast. The changes in sRAGE isoforms were inversely related to MG-H1 (rho=-0.493 to -0.589, p&amp;lt;0.05) and the change in esRAGE was inversely related to the change in G-H1 (rho=-0.474, p&amp;lt;0.05). Multiple regression analysis revealed a 1 pg/mL increase in total sRAGE, cRAGE, and esRAGE independently predicted a 0.42-0.52 nM decrease in MG-H1. Conclusions: Following an overnight fast, sRAGE isoforms were increased and sequestered MG-H1. Sequestration of AGEs by sRAGE has been shown to attenuate AGE/RAGE-mediated complications. Energy restriction appears to be important for protection against AGE/RAGE-mediated complications. Disclosure E.R. Miranda: None. K.N. Fuller: None. R. Perkins: None. P.J. Beisswenger: Employee; Self; PreventAGE Health Care, LLC.. S.S. Farabi: None. L.T. Quinn: None. J.M. Haus: None.

Circulating soluble RAGE and cell surface RAGE on peripheral blood mononuclear cells in healthy children.

The receptor for advanced glycation end products (RAGE) has a critical role in the pathogenesis of inflammation. In healthy children, its basal expression on the peripheral blood mononuclear cell (PBMC) and the basal circulating soluble RAGE (sRAGE) levels are unknown. The aim of this study was to describe both. This is a monocentric, observational and descriptive study of samples obtained from healthy children. The RAGE expression on PBMC was analyzed using flow cytometry. The sRAGE values were determined with a specific sandwich enzyme-linked immunosorbent assay (ELISA) kit, later the relation between cellular RAGE and sRAGE was described. Forty-three children were included. The median sRAGE level was 849.0±579.0 pg/mL. The RAGE mean fluorescence intensity (MFI) was 1382±506 in monocytes and 792±506 in lymphocytes. There were no differences between genders. A negative correlation was found between sRAGE and RAGE MFI in lymphocytes (r=-0.3; p=0.04). We describe for the first time the RAGE surface levels on PBMC in children. It showed a negative correlation with sRAGE. The sRAGE circulating level is lower than the sRAGE level described in adult population or non-healthy children. Our findings should be confirmed in order to apply them as reference values for future investigations.

Abstract 695: Rage-mDia1 Mediates Vascular Remodeling in Angiotensin Ii Induced Thoracic Aortic Aneurysm

Background: The Receptor for Advanced Glycation End Products (RAGE), when activated, induces irreversible vascular tissue injury by promoting pro-oxidative and pro-inflammatory signaling pathways. RAGE signal transduction requires the engagement of RAGE cytoplasmic domain with the formin Diaphanous 1 (mDia1) and results in the release of soluble RAGE in the circulation. We have previously demonstrated that the RAGE/sRAGE axis is involved in the development and progression of thoracic aortic aneurysm (TAA) in humans and mice. Elevated levels of sRAGE are found in aneurysmal patients and in mouse models of TAA. In addition, RAGE inhibition counteracts aortic dilatation and the release of sRAGE in the circulation. We hypothesize that RAGE induced vascular remodeling in TAA is mediated by mDia1. Methods: AngII infusion (1000 ng/Kg/min) was performed in C57BL6 male mice, fed with hypercolesterolaemic diet. Mice were treated for 4 weeks with losartan or with a RAGE antagonist (RAP). Ascending aortas of treated animals were harvested at day 28 post-infusion. Aortic dilatation and degeneration were assessed by echocardiography and histology. Immunofluorescence and Real Time PCR were performed to evaluate the expression of RAGE, mDia1, extracellular matrix proteins (ECM) and pro-inflammatory genes. Results: AngII infusion induces ascending aorta dilatation and medial thickening characterized by a substantial ECM deposition. RAGE and mDia1 expression is significantly increased in the aneurysmal aorta of mice chronically infused with AngII together with up-regulation of pro-inflammatory molecules (IL-6, MCP-1, IL1beta, TLR4, CCR2) and markers of extracellular matrix remodeling (Col1, Col3, MMP-2 and MMP12). Inhibition of RAGE dampens mDia1 expression and significantly reduces medial pro-inflammatory and pro-fibrotic signals while counteracting aneurysm formation. Conclusion: Formin mDia1 is involved in RAGE mediated TAA formation. Strategies that block RAGE-mDia1 interaction may unveil novel therapeutic approaches for the treatment of TAA.

373 - A new cellular therapy using soluble RAGE overexpressing-mesenchymal stem cells in a rat model of osteoarthritis

Mesenchymal stem cells (MSCs) can protect against cartilage breakdown in osteoarthritis (OA) via their immunomodulatory capacities. However, the optimization strategy for using MSCs remains challenging. The receptor for advanced glycation end products (RAGE) serves as a pattern recognition receptor for endogenous inflammatory ligands. Soluble RAGE (sRAGE) is a truncated form of RAGE, which functions as a decoy and acts as an anti-inflammatory molecule. We studied the therapeutic effect of sRAGE-overexpressing MSCs (sRAGE-MSCs) in experimental model of OA. An animal model of OA was established by intra-articular injection of monosodium iodoacetate into rats. OA rats were divided into a control group and two therapy groups, and sRAGE-MSCs or Mock-MSCs were given twice intravenously. The chondroprotective effects were greater in OA rats treated with sRAGE-MSCs than in those treated with Mock-MSCs. Furthermore, the mRNA expression of immunomodulatory molecules such as TGF-β, hepatocyte growth factor (HGF), and indoleamine 2,3-dioxygenase (IDO) was increased by sRAGE-MSC, compared to those of Mock-MSCs. These findings suggest that sRAGE overexpression in MSCs optimizes their immunoregulatory properties, which may be useful as a novel cellular therapy for OA.

Circulating levels of soluble rage decline with aging and predict age-associated cardiac remodelling

Circulating levels of soluble rage decline with aging and predict age-associated cardiac remodelling

Glycaemic control in type 2 diabetic patients with chronic kidney disease: the impacts on enzymatic antioxidants and soluble RAGE.

BackgroundChronic kidney disease (CKD) is characterised by long-term kidney damage and renal function decline. Diabetic CKD is the principal subtype of kidney disease in Malaysia and is associated with oxidative stress which plays an important role in development and progression of the disease. Glycaemic control slows down the progression of diabetic complications, including diabetic CKD. However, the implication of glycaemic control on enzymatic antioxidants and soluble RAGE (sRAGE) in CKD patients remains elusive. The aim of this study was to investigate the effect of glycaemic control on the levels or activities of glutathione peroxidase (GPx), superoxide dismutase (SOD) and sRAGE in CKD patients.MethodsA total of 150 CKD patients and 64 non-CKD patients were enrolled. The type 2 diabetic patients in the recruited study participants were categorised based on their glycaemic control; poor glycaemic control (GC) with haemoglobin A1c (HbA1c) > 7% and good GC with HbA1c ≤ 7%. The levels or activities of GPx, SOD and sRAGE in plasma were measured. These biochemical parameters were analysed using Mann–Whitney U test and two-way analysis of variance (ANOVA).ResultsThe activities of GPx and SOD as well as plasma level of sRAGE were not significantly different among the CKD patients with varying glycaemic control status. Irrespective of diabetes status and glycaemic control status, CKD patients also exhibited lower plasma SOD activities compared with non-CKD patients. Among the non-CKD patients, SOD activities were significantly higher in diabetic patients with good GC than diabetic patients with poor GC. Two-way ANOVA revealed that both CKD status and glycaemic control had an interaction effect on SOD activities in diabetic subjects with and without CKD. Follow-up analysis showed that SOD activities were significantly higher in non-CKD patients with good GC. There were no overall significant differences in GPx activities among the study participants. Furthermore, plasma sRAGE levels were higher in diabetic patients with CKD than those without CKD, regardless of glycaemic control status. There were no interaction effects between CKD status and glycaemic control status on GPx and sRAGE. Instead, CKD status showed significant main effects on these parameters, indicating significant differences between diabetic subjects with CKD and diabetic subjects without CKD.ConclusionGlycaemic control did not quantitatively alter GPx, SOD and sRAGE in diabetic CKD patients. Despite the advantages of good glycaemic control, a well-controlled diabetes in CKD did not modulate the activities of enzymatic antioxidants and sRAGE levels, therefore may not be the primary mechanism to handle oxidative stress.

A prospective study of soluble receptor for advanced glycation end products and adipokines in association with pancreatic cancer in postmenopausal women.

Advanced glycation end products (AGEs) dysregulate adipokines and induce inflammation by binding to their adipocyte receptor (RAGE). Soluble RAGE (sRAGE) prevents AGEs/RAGE signaling. We performed a nested case–control study of the association between sRAGE, adipokines, and incident pancreatic cancer risk in the prospective Women's Health Initiative Study. We individually matched controls (n = 802) to cases (n = 472) on age, race, and blood draw date. We evaluated serum concentrations of sRAGE, adiponectin, leptin, monocyte chemotactic protein 1 (MCP1), and plasminogen activator inhibitor‐1 (PAI1) using immunoassay. We used conditional logistic regression model to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for pancreatic cancer over biomarker quartiles (Q1–Q4). We used principal component analysis to create two composite biomarkers and performed a confirmatory factor analysis to examine the association between composite biomarker scores (CBS) and pancreatic cancer risk. Baseline serum sRAGE concentrations were inversely associated with pancreatic cancer risk (aORQ4 vs. Q1 = 0.70, 95% CI: 0.50–0.99). High MCP1 (aOR Q4 vs. Q1 = 2.55, 95% CI: 1.41–4.61) and the higher CBS including MCP1, PAI1, and leptin (aORQ4 vs. Q1 = 1.82, 95% CI = 1.04–3.18) were also associated with increased pancreatic cancer risk among women with BMI <25 kg/m2 (P values for interaction <0.05). We found an inverse association between prediagnostic sRAGE concentrations and risk of incident pancreatic cancer in postmenopausal women. A proinflammatory CBS was associated with increased risk only in women with normal BMI. MCP1 was not modulated by sRAGE.

Receptor of advanced glycation end products and cardiovascular risk in elderly with type 2 diabetes mellitus

The interaction of Advanced Glycation End products (AGEs) and their specific receptor, Receptor for Advanced Glycation End products (RAGE) play an important role in diabetes and vascular complications. Engagement of RAGE by AGEs leads to activation of cellular signaling pathways and vascular dysfunction. The soluble RAGE (sRAGE) acts as a decoy receptor for AGEs. The aim of this study was to evaluate the soluble RAGE in elderly subjects with T2DM and its relationships with glycoxidative, inflammatory and cardiovascular risk markers. The serum AGEs, sRAGE, interleukine- 6 (IL-6), lipid profile, glycemic status, uric acid, creatinine and cardiovascular risk markers were determined in elderly subjects with type 2 diabetes mellitus (T2DM, N=72, 75±4 years old) and aged-match healthy subjects (N=15, 76±3 years old). Significant higher levels of AGEs and AGEs/sRAGE ratio concomitantly with significant lower levels of sRAGE were pointed out in elderly subjects with T2DM as compared to control. The values of AGEs/sRAGE ratio were significantly positively associated (P&lt;0.05) with atherogenic, inflammatory and cardiovascular risk markers and significantly negatively with anti-atherogenic lipoproteins (P&lt;0.05). The multivariate regression analyses showed that atherogenic index was an independent predictor of sRAGE levels and AGEs/sRAGE ratio values. The associations of soluble RAGE and the AGEs/sRAGE ratio with atherogenic and inflammatory markers could reflect the protective role of soluble variants of RAGE in atherosclerosis and diabetes vascular complications.

Chronic Alcohol Ingestion Impairs Rat Alveolar Macrophage Phagocytosis via Disruption of RAGE Signaling

BackgroundAlcohol significantly impairs antioxidant defenses and innate immune function in the lung and increases matrix metalloproteinase 9 (MMP-9) activity. The receptor for advanced glycation end products (RAGE) is a well-characterized marker of lung injury that is cleaved by MMP-9 into soluble RAGE and has not yet been examined in the alcoholic lung. We hypothesized that chronic alcohol ingestion would impair RAGE signaling via MMP-9 in the alveolar macrophage and thereby impair innate immune function. Materials and MethodsPrimary alveolar macrophages were isolated from control-fed or alcohol-fed rats. Real-time polymerase chain reaction (qRT-PCR), Western blotting, and enzyme-linked immunosorbent assays were performed to evaluate RAGE expression. Silencing of MMP-9 ribonucleic acid (RNA) in a rat alveolar macrophage cell line was confirmed by qRT-PCR, and immunofluorescence (IF) was used to assess the association between alcohol, MMP-9, and RAGE. Phagocytosis was assessed using flow cytometry. Sulforaphane and glutathione were used to assess the relationship between oxidative stress and RAGE. ResultsRAGE messenger RNA expression was significantly increased in the alveolar macrophages of alcohol-fed rats, but IF showed that membrane-bound RAGE protein expression was decreased. Lavage fluid demonstrated increased levels of soluble RAGE (sRAGE). Decreasing MMP-9 expression using si-MMP-9 abrogated the effects of alcohol on RAGE protein. Phagocytic function was suppressed by direct RAGE inhibition, and the impairment was reversed by antioxidant treatment. ConclusionsChronic alcohol ingestion reduces RAGE protein expression and increases the amount of sRAGE in alveolar lavage fluid, likely via cleavage by MMP-9. In addition, it impairs phagocytic function. Antioxidants restore membrane-bound RAGE and phagocytic function.

Atorvastatin improves plaque stability in diabetic atherosclerosis through the RAGE pathway.

To study the improving effect of atorvastatin on plaque stability in diabetes mellitus (DM) mice complicated with atherosclerosis. Apolipoprotein E (ApoE)-/- mice were used to establish the DM mouse model. Half of the mice received atorvastatin after successful modeling. ApoE-/- and C57BL/6J mice were used as controls. Oil red O staining and Masson staining were performed to detect the lipid and collagen components in mice. Immunohistochemical assay was used to observe the expressions of smooth muscle cell (SMC) and Ly-6c. The expressions of receptor for advanced glycation end products (RAGE), monocyte chemoattractant protein-1 (MCP-1) and nuclear factor-κB (NF-κB) in tissues were detected by Western blotting. Finally, the levels of serum soluble RAGE (sRAGE), advanced glycation end products (AGEs), malondialdehyde (MDA) and reduced glutathione (GSH) in mice were also detected. Atorvastatin reduced the area of atherosclerotic plaque and improved the stability of arterial plaque through reducing lipid deposition, the number of macrophages and SMC, increasing collagen fibers. In mice in atorvastatin group, the levels of serum AGEs and sRAGE were decreased. Moreover, atorvastatin inhibited the downstream pathway of RAGE as well as DM, thus inducing the oxidative stress. Atorvastatin improves plaque stability in diabetic atherosclerosis through the RAGE pathway.

Association of Serum Soluble Receptor for Advanced Glycation End Products (sRAGE), S100A12, and VCAM-1 Levels with Further Post-Coronary Angiogram Endothelial Injury in Elderly and Younger Patients

Objective: Coronary Angiography (CAG) refers to an aggressive process that is likely to lead to endothelial injury and possibly drive further interpretation of the cause for patients within current atherosclerotic illnesses. Therefore, this study aims to test certain correlations among concentration of sRAGE, VCAM-1, as well as S100A12 pre- and post-coronary angiography alongside likelihood of endothelial injury among various patients in different ages including the younger and the geriatric groups, thereby offering a full connection upon CAG impacts of patients having atherosclerosis. Method: In this study, the whole patients chosen had been grouped into two major groups on the basis of ages: the younger patient aged less than 65 years old (Group 1), and the elderly patient aged over 65 years old (Group 2). Soluble RAGE (sRAGE), VCAM-1 and S100A12 degrees in blood sampling gathered followed by measurements of CAG session for evaluating the inflammatory responses and likelihood of endothelial injury caused via CAG. All data was analyzed using SPSS version 21.0. Findings: Significant enhancement among concentration of serum VCAM-1 (P = 0.007) in younger patients and sRAGE (P = 0.019) in elderly patients had been observed, but that of serum S100A12 was still unaltered. Conclusions: Enhanced concentration of sRAGE and VCAM-1 post-CAG of patients having CAD are able to be related to follow-up endothelial injury, thus contributing to different pathway in exacerbating endothelial injury among younger and elderly patients.

Inhibition of the Receptor for Advanced Glycation End-Products in Acute Respiratory Distress Syndrome: A Randomised Laboratory Trial in Piglets

Background: The receptor for advanced glycation end products (RAGE) modulates the pathogenesis of acute respiratory distress syndrome (ARDS). RAGE inhibition was recently associated with attenuated lung injury and restored alveolar fluid clearance (AFC) in a mouse model of ARDS. However, clinical translation will first require assessment of this strategy in larger animals. Methods: Forty-eight anaesthetised Landrace piglets were randomised into a control group and three treatment groups. Animals allocated to treatment groups underwent orotracheal instillation of hydrochloric acid i) alone; ii) in combination with intravenous administration of a RAGE antagonist peptide (RAP), a S100P-derived peptide that prevents activation of RAGE by its ligands, or iii) in combination with intravenous administration of recombinant soluble (s)RAGE that acted as a decoy receptor. The primary outcome measure was net AFC at 4 h. Arterial oxygenation was assessed hourly for 4 h and alveolar-capillary permeability, alveolar inflammation, lung histology and lung mRNA expression of the epithelial sodium channel (α1-ENaC), α1-Na,K-ATPase and aquaporin (AQP)-5 were assessed at 4 h. Findings: Treatment with either RAP or sRAGE improved net AFC rates (median [interquartile range], 21.2 [18.8-21.7] and 19.5 [17.1-21.5] %/h, respectively, versus 12.6 [3.2-18.8] %/h in injured, untreated controls), improved oxygenation and decreased alveolar inflammation and histological evidence of tissue injury after acid-induced ARDS. RAGE inhibition also restored lung mRNA expression of α1-Na, K-ATPase and AQP-5. Interpretation: RAGE inhibition restored AFC and attenuated lung injury in a piglet model of acid-induced ARDS. Funding: Auvergne Regional Council, Agence Nationale de la Recherche, Direction Generale de l'Offre de Soins. Declaration of Interest: No conflict of interest, other source of financial support, corporate involvement, patent holdings, etc. is to be declared for all authors. Ethical Approval: Animals were maintained and all procedures were performed with the approval of the ethics committee of the French Ministere de l’Education Nationale, de l’Enseignement Superieur et de la Recherche in the Centre International de Chirurgie Endoscopique, School of Medicine - University of Clermont-Ferrand (approval number 01505.03). All experiments were performed in accordance with the “Animal Research: Reporting In Vivo Experiments” (ARRIVE) guidelines.

Soluble Receptor for Advanced Glycation End Products (sRAGE) is Up-Regulated in Multiple Sclerosis Patients Treated with Interferon β-1a

Background/Aims: Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system. Considering the role of immune system in its pathogenesis, researchers have focused on evaluation of the expression of immune-related genes or proteins in MS patients. Among proteins whose participation in inflammatory process has been documented is the receptor for advanced glycation end products (RAGE). Methods: In the present study, we compared RAGE transcript levels by means of quantitative real-time PCR as well as the serum level of soluble RAGE (sRAGE) by means of enzyme- linked immunosorbent assay (ELISA) in 50 IFNβ-1a responsive relapsing-remitting MS patients when compared with age and sex-matched healthy subjects. Results: Elevated expression of RAGE as well as higher levels of sRAGE were detected in IFN-β responsive MS patients compared with the controls. A significant inverse correlation between sRAGE plasma concentrations and the expanded disability status scale (EDSS) was also detected in which each unit of increase in sRAGE level resulted in a 0.308 unit decrease in EDSS. Conclusion: Considering the stable clinical state of the MS patients in this study and their response to IFNβ-1a, the elevated levels of sRAGE in patients compared with healthy subjects could be related to the effects of this kind of treatment.