High sRAGE Research Articles

Frailty Influences the Relationship between the Soluble Receptor for Advanced Glycation-End Products and Mortality in Older Adults with Diabetes Mellitus

Introduction: Frailty is prevalent among older adults with diabetes mellitus. Elevated serum levels of the soluble receptor for advanced glycation-end products (sRAGE) predict mortality in frail older adults. The evidence that sRAGE is also related to higher mortality in older adults with diabetes mellitus is inconsistent. Therefore, this study explored if frailty status influences the relationship between sRAGE and mortality in older adults with this condition. Methods: We analysed data of 391 participants with diabetes mellitus (median age, 76 years) from four European cohorts enrolled in the FRAILOMIC project. Frailty was evaluated at baseline using Fried’s criteria. Serum sRAGE was determined by ELISA. Participants were stratified by frailty status (n = 280 non-frail and 111 frail). Multivariate Cox proportional hazards regression and Kaplan-Meier survival analysis were used to assess the relationship between sRAGE and mortality. Results: During 6 years of follow-up, 98 participants died (46 non-frail and 52 frail). Non-survivors had significantly higher baseline levels of sRAGE than survivors (median [IQR]: 1,392 [962–2,043] pg/mL vs. 1,212 [963–1,514], p = 0.008). High serum sRAGE (>1,617 pg/mL) was associated with increased mortality in the whole diabetes sample after adjustment for relevant confounders (HR 2.06, 95% CI: 1.36–3.11, p < 0.001), and there was an interaction between sRAGE and frailty (p = 0.006). Accordingly, the association between sRAGE and mortality was stronger in the frail group compared to the non-frail group (HR 2.52, 95% CI: 1.30–4.90, p = 0.006 vs. HR 1.71, 95% CI: 0.91–3.23, p = 0.099, respectively). Likewise, Kaplan-Meier curves showed a significant difference in survival rates between frail participants with high sRAGE and those with low sRAGE (p = 0.001), whereas no survival difference was seen in the non-frail group (p = 0.09). Conclusions: Frailty status influences the relationship between sRAGE and mortality in older adults with diabetes mellitus. Determination of sRAGE in this population could be a useful tool for risk stratification.

The soluble receptor for advanced glycation end products is potentially predictive of pulmonary arterial hypertension in systemic sclerosis.

Pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD) are the leading causes of death in systemic sclerosis (SSc). Until now, no prospective biomarker to predict new onset of SSc-ILD or SSc-PAH in patients with SSc has reached clinical application. In homeostasis, the receptor for advanced glycation end products (RAGE) is expressed in lung tissue and involved in cell-matrix adhesion, proliferation and migration of alveolar epithelial cells, and remodeling of the pulmonary vasculature. Several studies have shown that sRAGE levels in serum and pulmonary tissue vary according to the type of lung-related complication. Therefore, we investigated levels of soluble RAGE (sRAGE) and its ligand high mobility group box 1 (HMGB1) in SSc and their abilities to predict SSc-related pulmonary complications. One hundred eighty-eight SSc patients were followed retrospectively for the development of ILD, PAH, and mortality for 8 years. Levels of sRAGE and HMGB1 were measured in serum by ELISA. Kaplan-Meier survival curves were performed to predict lung events and mortality and event rates were compared with a log-rank test. Multiple linear regression analysis was performed to examine the association between sRAGE and important clinical determinants. At baseline, levels of sRAGE were significantly higher in SSc-PAH-patients (median 4099.0 pg/ml [936.3-6365.3], p = 0.011) and lower in SSc-ILD-patients (735.0 pg/ml [IQR 525.5-1988.5], p = 0.001) compared to SSc patients without pulmonary involvement (1444.5 pg/ml [966.8-2276.0]). Levels of HMGB1 were not different between groups. After adjusting for age, gender, ILD, chronic obstructive pulmonary disease, anti-centromere antibodies, the presence of puffy fingers or sclerodactyly, use of immunosuppression, antifibrotic therapy, or glucocorticoids, and use of vasodilators, higher sRAGE levels remained independently associated with PAH. After a median follow-up of 50 months (25-81) of patients without pulmonary involvement, baseline sRAGE levels in the highest quartile were predictive of development of PAH (log-rank p = 0.01) and of PAH-related mortality (p = 0.001). High systemic sRAGE at baseline might be used as a prospective biomarker for patients with SSc at high risk to develop new onset of PAH. Moreover, high sRAGE levels could predict lower survival rates due to PAH in patients with SSc.

Concentrations of N6-Carboxymethyllysine (CML), N6-Carboxyethyllysine (CEL), and Soluble Receptor for Advanced Glycation End-Products (sRAGE) Are Increased in Psoriatic Patients.

Psoriasis is a chronic, recurrent, and often severe skin disease which is frequently associated with metabolic disorders and increased risk of cardiovascular complications. One of the postulated links is an intensified process of advanced protein glycation and/or glycoxidation. Therefore, the aim of the study was to assess concentrations of N6-carboxymethyllysine (CML), N6-carboxyethyllysine (CEL), and soluble form of receptor for advanced glycation end-products (sRAGE) in psoriasis patients at different phases of the disease activity, in comparison to healthy individuals. The study material consisted of sera from psoriasis patients in active phase, in the remission phase, and healthy controls. Concentrations of CML, CEL, and sRAGE were determined using ELISA technique. In the patients with psoriasis (in both phases of the disease), concentrations of CML, CEL and sRAGE were significantly higher than in healthy individuals but they did not correlate with psoriasis area severity index (PASI) values. The remission of the disease was followed by a significant decrease in CML, CEL, and sRAGE concentrations when compared to active patients; however, these concentrations were still significantly higher than in the controls. Our data suggest that psoriasis is accompanied by an intense glycoxidation process and that high sRAGE levels seem to reflect permanent RAGE overstimulation.

Advanced glycation end products, leukocyte telomere length, and mitochondrial DNA copy number in patients with coronary artery disease and alterations of glucose homeostasis: From the GENOCOR study

Background and aimAlterations of glucose homeostasis can increase advanced glycation end products (AGEs) that exacerbate vascular inflammatory disease and may increase vascular senescence and aging. This study examined the relationships between carboxymethyl-lysine (CML) and soluble receptor for AGEs (sRAGE) with leukocyte telomere length (LTL) and mitochondrial DNA copy number (mtDNAcn), as cell aging biomarkers, in patients with established coronary artery disease (CAD). Methods and resultsWe studied 459 patients with CAD further categorized as having normal glucose homeostasis (NG, n = 253), pre-diabetes (preT2D, n = 85), or diabetes (T2D, n = 121). All patients were followed up for the occurrence of major adverse cardiovascular events (MACEs). Plasma concentrations of sRAGE and CML were measured by ELISA. mtDNAcn and LTL were measured by qRT-PCR. CML levels were significantly higher in patients with preT2D (p < 0.007) or T2D (p < 0.003) compared with those with NG. mtDNAcn resulted lower in T2D vs preT2D (p = 0.04). At multivariate Cox proportional hazard analysis, short LTL (HR: 2.89; 95% CI: 1.11–10.1; p = 0.04) and high levels of sRAGE (HR: 2.20; 95% CI: 1.01–5.14; p = 0.04) were associated with an increased risk for MACEs in patients with preT2D and T2D, respectively. T2D patients with both short LTL and high sRAGE levels had the highest risk of MACEs (HR: 3.11; 95% CI: 1.11–9.92; p = 0.04). ConclusionsHigh levels of sRAGE and short LTL were associated with an increased risk of MACEs, especially in patients with diabetes, supporting the usefulness of both biomarkers of glycemic impairment and aging in predicting cardiovascular outcomes in patients with CAD.

Higher sRAGE Levels Predict Mortality in Frail Older Adults with Cardiovascular Disease

Introduction: The evidence that blood levels of the soluble receptor for advanced glycation end products (sRAGE) predict mortality in people with cardiovascular diseases (CVD) is inconsistent. To clarify this matter, we investigated if frailty status influences this association. Methods: We analysed data of 1,016 individuals (median age, 75 years) from 3 population-based European cohorts, enrolled in the FRAILOMIC project. Participants were stratified by history of CVD and frailty status. Mortality was recorded during 8 years of follow-up. Results: In adjusted Cox regression models, baseline serum sRAGE was positively associated with an increased risk of mortality in participants with CVD (HR 1.64, 95% CI 1.09–2.49, p = 0.019) but not in non-CVD. Within the CVD group, the risk of death was markedly enhanced in the frail subgroup (CVD-F, HR 1.97, 95% CI 1.18–3.29, p = 0.009), compared to the non-frail subgroup (CVD-NF, HR 1.50, 95% CI 0.71–3.15, p = 0.287). Kaplan-Meier analysis showed that the median survival time of CVD-F with high sRAGE (>1,554 pg/mL) was 2.9 years shorter than that of CVD-F with low sRAGE, whereas no survival difference was seen for CVD-NF. Area under the ROC curve analysis demonstrated that for CVD-F, addition of sRAGE to the prediction model increased its prognostic value. Conclusions: Frailty status influences the relationship between sRAGE and mortality in older adults with CVD. sRAGE could be used as a prognostic marker of mortality for these individuals, particularly if they are also frail.

The receptor for advanced glycation end product (RAGE) pathway in COVID-19

Introduction Coronavirus disease-2019 (COVID-19) with lung involvement frequently causes morbidity and mortality. Advanced age appears to be the most important risk factor. The receptor for advanced glycation end-product (RAGE) pathway is considered to play important roles in the physiological aging and pathogenesis of lung diseases. This study aimed to investigate the possible relationship between COVID-19 and RAGE pathway. Materials and methods This study included 23 asymptomatic patients and 35 patients with lung involvement who were diagnosed with COVID-19 as well as 22 healthy volunteers. Lung involvement was determined using computed tomography. Serum soluble-RAGE (sRAGE) levels were determined using enzyme-linked immunosorbent assay. Results The sRAGE levels were significantly higher in the asymptomatic group than in the control group. Age, fibrinogen, C-reactive protein, and ferritin levels were higher and the sRAGE level was lower in the patients with lung involvement than in the asymptomatic patients. Conclusions In this study, patients with high sRAGE levels were younger and had asymptomatic COVID-19. Patients with low sRAGE levels were elderly patients with lung involvement, which indicates that the RAGE pathway plays an important role in the aggravation of COVID-19.

High BAL sRAGE is Associated with Low Serum Eosinophils and IgE in Children with Asthma.

Asthma remains the most common chronic lung disease in childhood in the United States. The receptor for advanced glycation end products (RAGE) has been recognized as both a marker of and participant in pulmonary pathophysiology. While membrane-bound RAGE (mRAGE) perpetuates the type 2 immune response, the soluble form (sRAGE) may act as a decoy receptor for pro-inflammatory ligands. Bronchoalveolar samples from 45 pediatric patients with asthma were obtained. Patients were divided into high and low BAL sRAGE groups using median sRAGE. Descriptive statistical analysis and non-parametric testing were applied. Children in the “high” sRAGE group had a lower median serum eosinophil (0.27 [SE ± 0.04] vs. 0.57 [± 0.06] K/mcl, adjusted p = 0.003) and lower serum IgE level (194.4 [± 60.7] vs. 676.2 ± 140.5) IU/mL, adjusted p = 0.004) as compared to the “low” sRAGE group. When controlling for age and body mass index percentile, absolute eosinophil count (p = 0.03) and serum IgE (p = 0.043) remained significantly lower in the “high” sRAGE group. Children with asthma and high levels of BAL sRAGE have lower serum eosinophil and IgE levels. These findings are consistent with the hypothesis that sRAGE may act as a decoy receptor by binding ligands that normally interact with mRAGE.

Soluble receptor for advanced glycation end-products independently influences individual age-dependent increase of arterial stiffness.

Circulating levels of soluble receptor for advanced glycation end-products (sRAGE) have been suggested to have a protective role in neutralizing advanced glycation end-products (AGEs) and their pathological effects on vessel walls. We aimed to investigate the association between the circulating concentration of sRAGE and the dynamics of arterial wall stiffening as a manifestation of vascular aging in the general population. In a prospective cohort study, we longitudinally followed 530 general-population-based subjects (subsample of Czech post-MONICA study). Aortic pulse wave velocity (PWV) was measured twice (at baseline and after ~8 years of follow-up) using a SphygmoCor device (AtCor Medical Ltd), and the intraindividual change in PWV per year (∆PWV/year) was calculated. Concentrations of sRAGE were assessed at baseline by ELISA (R&D Systems). The average ∆PWV/year significantly decreased across the sRAGE quintiles (p = 0.048), and a drop by one sRAGE quintile was associated with an ~21% increase in the relative risk of accelerated age-dependent stiffening (∆PWV/year ≥ 0.2 m/s). Subjects in the bottom quintile of sRAGE (<889.74 pg/mL) had a fully adjusted odds ratio of accelerated stiffening of 1.72 (95% CI: 1.06-2.79), p = 0.028, while those with high sRAGE concentrations (≥1695.2 pg/mL) showed the opposite effect [odds ratio 0.55 (95% CI: 0.33-0.90), p = 0.017]. In conclusion, the circulating status of sRAGE independently influenced the individual progression of arterial stiffness over time. This finding strongly supports the hypothesis that high sRAGE has a protective role against vascular aging.

The soluble receptor for advanced glycation end-products (sRAGE) has a dual phase-dependent association with residual cardiovascular risk after an acute coronary event

Background and aimsThe pro-inflammatory alarmin S100A12 (EN-RAGE) and the soluble form of its receptor, the receptor for advanced glycation endproducts (sRAGE), have diverging roles in cardiovascular disease. In experimental studies, S100A12 promoted atherosclerosis while sRAGE treatment was anti-atherogenic and reduced myocardial infarction size by scavenging RAGE ligands. Here, we aimed to explore the links between S100A12, sRAGE, and long-term prognosis after an acute coronary syndrome (ACS). MethodsWe measured S100A12 and sRAGE in 524 patients within 24 h after an ACS, and again 6 weeks later in a subgroup of 114 patients. This subgroup also completed a follow-up echocardiography after 1 year. The median follow-up time for recurrent major adverse cardiovascular events (MACE), defined as recurrent ACS or cardiovascular death, was 25.7 ± 12.6 months. ResultsIn Cox proportional hazard analyses, baseline S100A12 and sRAGE were positively associated with the risk of MACE, independently of traditional cardiovascular risk factors. The association between sRAGE and MACE remained significant after additional adjustment for troponin T, NT-proBNP and hsCRP [HR 95%CI for highest versus lowest tertile 3.2 (1.5–6.5), p = 0.002]. High sRAGE was also associated with deteriorating left ventricular function and an increased rate of heart failure hospitalization post-discharge. In contrast, patients with increasing sRAGE at 6 weeks compared to baseline had lower incidence of recurrent ACS. ConclusionsOur data suggest that sRAGE has a dual, phase-dependent association with residual cardiovascular risk after ACS. These findings are important for the design and interpretation of future studies on sRAGE as biomarker and potential treatment in ACS patients.

High Plasma sRAGE (Soluble Receptor for Advanced Glycation End Products) Is Associated With Slower Carotid Intima-Media Thickness Progression and Lower Risk for First-Time Coronary Events and Mortality.

Objective- RAGE (receptor for advanced glycation end products) and EMMPRIN (extracellular matrix metalloproteinase inducer) are immune receptors for proinflammatory mediators. These receptors can also be found in a soluble form in the circulation. Soluble RAGE (sRAGE) has shown atheroprotective properties in animal studies, possibly by acting as a decoy receptor for its ligands. Whether sEMMPRIN (soluble EMMPRIN) has similar roles is unknown. We hypothesized that sRAGE and sEMMPRIN might be associated with vascular disease progression, incident coronary events, and mortality. Approach and Results- We measured baseline sRAGE and sEMMPRIN in 4612 cardiovascular disease-free individuals from the population-based Malmö Diet and Cancer cohort. Measurements of intima-media thickness in the common carotid artery were performed at inclusion and after a median of 16.5 years. sRAGE was negatively correlated with carotid intima-media thickness progression, independently of traditional cardiovascular risk factors, kidney function, and hsCRP (high sensitive C-reactive protein). Additionally, sRAGE was associated with decreased risk for major adverse coronary events (hazard ratio=0.90 [0.82-0.97]; P=0.009) and mortality (hazard ratio=0.93 [0.88-0.99]; P=0.011) during a follow-up period of 21 years. The relationship with mortality was independent of all considered potential confounders. We found no correlations between EMMPRIN, intima-media thickness progression, or prognosis. Conclusions- Individuals with high levels of circulating sRAGE have a slower rate of carotid artery disease progression and a better prognosis. Although its predictive value was too weak to promote sRAGE as a useful clinical biomarker in the population, the findings support further research into the potential anti-inflammatory and atheroprotective properties of this soluble receptor.

Soluble receptor for advanced glycation end products as a vasculopathy biomarker in sickle cell disease.

Soluble forms of RAGE (sRAGE) have been found circulating in plasma and tissues. Evidence is accruing in human subjects linking levels of sRAGE to oxidative stress in many disorders. Because sickle cell disease (SCD) is a state of oxidative stress, we tested the hypothesis that circulating sRAGE levels may be involved in the vascular pathology of SCD. To determine the sRAGE levels in children and adolescents with SCD and investigate their association with markers of hemolysis, iron overload, and SCD-related organ complications. The level of sRAGE was measured in 40 children and adolescent with SCD compared with 40 healthy controls using enzyme-linked immunosorbent assay (ELISA). sRAGE was significantly higher in patients compared with controls (p < 0.001) and was elevated in patients with history of stroke, acute lung syndrome, and frequency of sickling crisis or serum ferritin > 2500 (p < 0.05). Patients with high sRAGE levels are candidates for chelation. sRAGE was positively correlated with HbS% (r = 0.422, p = 0.007), LDH (r = 0.329, p = 0.038), and serum ferritin levels (r = 0.516, p = 0.001). Multivariable regression analysis proved that both HbS% and serum ferritin were significant independent factors affecting sRAGE level (p < 0.05). Our findings suggest that sRAGE may be considered as a marker for vascular dysfunction in SCD patients.

Is there any evidence that AGE/sRAGE is a universal biomarker/risk marker for diseases?

Advanced glycation end products (AGE) and its cell-bound receptor called receptor for AGE (RAGE) are implicated in the pathogenesis of numerous diseases. Soluble receptor for AGE (sRAGE) counteracts the adverse effects of AGE-RAGE interaction by competing with RAGE for binding with AGE. Low levels of serum sRAGE have been proposed as a biomarker for diseases. However, the serum levels of sRAGE in diabetes and end-stage renal disease (ESRD) are elevated. Thus, low levels of sRAGE cannot be a universal biomarker. An elevated ratio of AGE/sRAGE was then proposed as a universal biomarker. However, evidence was not provided for this new biomarker. The objective of this paper is to provide evidence in support of elevated AGE/sRAGE being a universal biomarker. The data for serum levels of AGE, sRAGE, and ratio of AGE/sRAGE were collected from patients with low serum sRAGE [non-ST-elevation myocardial infarction (NSTEMI), hyperthyroidism (HT), thoracic aortic aneurysm (TAA),and hypercholesterolemia (HC)], and with high serum levels of sRAGE [type-2 diabetes (T2D) and ESRD], and control subjects. The serum levels of AGE and ratio of AGE/sRAGE were higher in all types of patients irrespective of low or high serum sRAGE as compared to control subjects. Reasons are provided as to why AGE or sRAGE individually cannot be considered as a universal biomarker. In conclusion, the evidence supports the validity of the high ratio AGE/sRAGE as a universal biomarker/risk marker for diseases.

Decreased levels of sRAGE in follicular fluid from patients with PCOS.

This study aimed to explore the association between soluble receptor for advanced glycation end products (sRAGE) levels in follicular fluid and the number of oocytes retrieved and to evaluate the effect of sRAGE on vascular endothelial growth factor (VEGF) in granulosa cells in patients with polycystic ovarian syndrome (PCOS). Two sets of experiments were performed in this study. In part one, sRAGE and VEGF protein levels in follicular fluid samples from 39 patients with PCOS and 35 non-PCOS patients were measured by ELISA. In part two, ovarian granulosa cells were isolated from an additional 10 patients with PCOS and cultured. VEGF and SP1 mRNA and protein levels, as well as pAKT levels, were detected by real-time PCR and Western blotting after cultured cells were treated with different concentrations of sRAGE. Compared with the non-PCOS patients, patients with PCOS had lower sRAGE levels in follicular fluid. Multi-adjusted regression analysis showed that high sRAGE levels in follicular fluid predicted a lower Gn dose, more oocytes retrieved, and a better IVF outcome in the non-PCOS group. Logistic regression analysis showed that higher sRAGE levels predicted favorably IVF outcomes in the non-PCOS group. Multi-adjusted regression analysis also showed that high sRAGE levels in follicular fluid predicted a lower Gn dose in the PCOS group. Treating granulosa cells isolated from patients with PCOS with recombinant sRAGE decreased VEGF and SP1 mRNA and protein expression and pAKT levels in a dose-dependent manner.

Relationships between vitreous levels of soluble receptor for advanced glycation end products (sRAGE) and renal function in patients with diabetic retinopathy.

We investigated the relationship between vitreous levels of soluble receptor for advanced glycation end products (sRAGE) and vascular endothelial growth factor (VEGF) and renal function, and correlations between vitreous sRAGE levels and proliferative diabetic retinopathy (PDR) activity. We examined 33 eyes from 33 patients with diabetes mellitus who underwent a vitrectomy (eight patients in the non-PDR [NPDR] group and 25 in the PDR group). Serum creatinine levels and estimated glomerular filtration rate (eGFR) were measured and classified according to the chronic kidney disease (CKD)-staging method. Enzyme-linked immunosorbent assay (ELISA) was performed to quantify vitreous sRAGE and VEGF levels. Vitreous sRAGE levels were significantly higher in PDR group compared to NPDR group (p=0.00003). Vitreous sRAGE levels were significantly higher in patients with CKD stage 5 (end-stage renal failure or hemodialysis) than in patients with CKD stage 1 or 2 (p<0.01) and 3 or 4 (p<0.05), and were significantly correlated with eGFR (r=-0.490, p=0.007) and creatinine levels (r=0.484, p=0.006). Within the PDR group, patients with low (<27pg/mL) sRAGE levels required repeat vitreous surgeries for early postoperative vitreous hemorrhage significantly more frequently than those with high (≥27pg/mL) sRAGE levels (p=0.0067). Vitreous sRAGE levels were significantly correlated with renal function, and low vitreous sRAGE levels in patients with PDR were associated with postoperative vitreous hemorrhage. Vitreous sRAGE may be a useful biomarker for renal dysfunction associated with diabetic retinopathy.

High plasma level of soluble RAGE is independently associated with a low recurrence of atrial fibrillation after catheter ablation in diabetic patient.

Atrial fibrillation (AF) is closely associated with metabolic syndrome, and the receptor for advanced glycation end products (RAGE) pathway is involved in insulin resistance and cardiac remodelling. We hypothesized that plasma level of soluble RAGE (sRAGE) would predict clinical outcome after radiofrequency catheter ablation for AF. We measured pre-procedural plasma level of sRAGE in 496 patients who underwent AF ablation (142 patients with diabetes, 354 patients without diabetes selected by matching them with diabetic patients according to age, sex, and AF type). (i) Plasma level of sRAGE was significantly higher in diabetic patients than in non-diabetics (580.0 ± 576.4 vs. 435.8 ± 280.7 pg/mL, P = 0.005), but there was no difference in sRAGE levels between patients with clinical recurrence of AF and those without. (ii) During 24.5 ± 18.0 months of follow-up, the recurrence of AF was significantly lower in the diabetic patient group with high sRAGE (≥418 pg/mL based on the median value) than the diabetic patient group with low sRAGE (log-rank P = 0.045). This was especially pronounced in patients with paroxysmal AF and diabetes (log-rank P = 0.016), but no association was found in non-diabetics. (iii) In multivariate Cox regression analysis, high sRAGE (HR 0.395, 95% CI 0.175-0.894, P = 0.026) and paroxysmal AF (HR 0.387, 95% CI 0.179-0.835, P = 0.016) were independently associated with the favourable clinical outcome of rhythm control after AF ablation in diabetic patients. High plasma level of sRAGE was independently associated with low AF recurrence after catheter ablation in diabetic patients, especially those with paroxysmal AF.

Abstract P350: Association of Plasma Levels of Soluble Receptor for Advanced Glycation End Products and Risk of Kidney Disease is Explained by Baseline Kidney Function

Introduction: Advanced glycation end products and their cell-bound receptors (RAGE) are thought to mediate the adverse effects of dysglycemia and vascular disease through oxidative stress, inflammation, and endothelial dysfunction. The soluble form of RAGE (sRAGE) is a 48-kDa, positively-charged cleavage product of RAGE. There is limited evidence on the role of sRAGE in the pathogenesis of kidney disease. Methods: We conducted cross-sectional and prospective analyses of a case-cohort study nested within the ARIC Study. Plasma sRAGE was measured at baseline (1990-92) in a cohort random sample (n=1,218) and three case groups of participants with incident chronic kidney disease [estimated glomerular filtration rate (eGFR) &lt;60 mL/min/1.73 m 2 and ≥25% eGFR decline; n=151], incident end-stage renal disease [U.S. Renal Data System registry; n=152], and incident kidney failure (eGFR &lt;15 mL/min/1.73 m 2 , U.S. Renal Data System registry, or kidney failure-related hospitalization or death; n=266). Results: Baseline sRAGE levels were inversely related to baseline eGFR (r = -0.13). After adjusting for age, sex, and race, one interquartile range increase in log 10 -transformed sRAGE was associated with development of end-stage renal disease [hazard ratio: 1.97; 95% confidence interval (CI): 1.47, 2.64; p&lt;0.001], kidney failure (hazard ratio: 1.59; 95% CI: 1.27, 2.00; p&lt;0.001), and chronic kidney disease (odds ratio: 1.39; 95% CI: 1.06, 1.83; p=0.02). However, none of these associations were significant after additional adjustment for eGFR (all p&gt;0.10; Figure). Conclusions: High sRAGE levels are associated with decreased kidney function. The association of sRAGE with kidney disease risk may be explained by its partial clearance by the kidney.

Abstract 247: Association of Soluble RAGE Levels with Carotid Atherosclerosis: The Northern Manhattan Study (NOMAS)

Introduction The Receptor for Advanced Glycation End-products (RAGE) is a multi-ligand receptor that propagates vascular cell dysfunction leading to proinflammatory disease states. RAGE is produced as a membrane bound and soluble isoform (soluble RAGE (sRAGE)), with the soluble isoform demonstrated to act as a RAGE decoy preventing cellular activation and atherosclerosis. Recent cohort studies have suggested that serum levels of sRAGE are associated with the risk of CVD and therefore may be a novel biomarker for cardiovascular disease states. Hypothesis We hypothesized that sRAGE levels are associated with subclinical atherosclerosis in an ethnically diverse population. Methods We included 1,102 stroke-free participants from the multi-ethnic Northern Manhattan Study (NOMAS) who underwent high-resolution carotid B-mode ultrasound to measure carotid plaque phenotypes (density, thickness, and area) and carotid intima-media thickness (IMT). Plaque density was characterized by Gray Scale Median (GSM). Serum sRAGE was measured by ELISA and log-transformed to stabilize variance. Multiple linear and logistic regressions were employed to estimate sRAGE associations with IMT and plaque measures. Results The mean age at time of ultrasound was 70.7±8.6yrs; 65% were Hispanic, 19% black, and 16% white. The majority of subjects had carotid plaque present (54%) with the median GSM 38(0-190). Mean plaque thickness (IQR) was 1.30(0-3.99)mm and mean area (IQR) 2.43(0-96.75)mm2. Mean IMT was 0.93±0.09mm. High sRAGE levels were associated with more echolucent plaques (OR 1.2, 95% CI 1.03-1.42), especially among Hispanics (OR 1.26, 95% CI 1.04-1.54). These relationships remained after adjusting for sociodemographic and vascular risk factors. No association was seen between sRAGE levels and carotid IMT, plaque thickness or area. Conclusion In the present study, higher sRAGE levels were associated with echolucent (lower density) plaque, especially among Hispanic subjects. Our data suggest sRAGE levels may be associated with atherosclerotic plaque morphology and its vulnerability, especially among minority groups. These findings further support RAGE as a novel target for anti-atherosclerosis interventions.

Intrafollicular soluble receptor for advanced glycation end products (sRAGE) and embryo quality in assisted reproduction

The developmental potential of human embryos has important implications in assisted reproduction and depends, among other factors, on oocyte competency. The receptor for advanced glycation end products (RAGE) is a member of the superfamily of immunoglobulin cell-surface molecules that are constitutively expressed during embryonic development. RAGE is down-regulated in homeostasis in adult life. This study measured the concentration of soluble RAGE (sRAGE) in follicular fluid obtained from the leading follicle after ovarian stimulation of 54 women undergoing intracytoplasmic sperm injection. Corresponding embryos and sRAGE concentrations in follicular fluid were evaluated and correlations were investigated by multi-adjusted regression analysis. High intrafollicular sRAGE concentrations predicted poor-quality embryos (n=45, OR=0.986; P=0.026), adjusted for patient age, body mass index and oocyte quality, showing an inverse association between intrafollicular sRAGE concentrations and embryo development.The developmental potential of human embryos has important implications in assisted reproduction, and it depends, among other factors, on oocyte competency. The receptor for advanced glycation end products (RAGE) is a molecule constitutively expressed during embryonic development, but it is down-regulated in adult life. RAGE is frequently associated with pro-inflammatory responses, and it is implicated as an underlying condition in immune disorders, cardiovascular diseases, diabetes, Alzheimer’s disease and cancer. In addition to activating the pro-inflammatory responses, RAGE down-regulates cellular defence mechanisms. The present study measured the concentrations of soluble RAGE (sRAGE) in follicular fluid samples obtained from leading follicles of women undergoing intracytoplasmic sperm injection (ICSI). This prospective cohort study included 54 patients undergoing ICSI, and follicular fluid samples were obtained from the leading follicle after ovarian stimulation. The corresponding embryos were evaluated and correlations with intrafollicular sRAGE concentrations were investigated using multi-adjusted regression analysis. We observed that high intrafollicular concentrations of sRAGE predicted poor embryo quality. Our findings suggest an association between high concentrations of intrafollicular sRAGE and poor embryo development following ovarian stimulation for ICSI.

The soluble form of the receptor of advanced glycation endproducts increases after bariatric surgery in morbid obesity

The increased cardiovascular (CV) disease risk in patients with morbid obesity (MO) cannot be fully explained by traditional CV risk factors. Activation of the receptor of Advanced Glycation Endproducts (RAGE) leads to inflammation via the NF κβ (nuclear factor κβ) pathway. The soluble form of RAGE (sRAGE), which is present in plasma, can bind to ligands of RAGE and avoids interaction of RAGE with proinflammatory ligands. We investigated sRAGE levels in patients with MO and compared them with healthy lean controls (CO), before and after bariatric surgery. We conducted a cross-sectional study and a 24-month longitudinal study. We included 85 patients (mean age: 41 ± 12 years; mean body mass index (BMI): 45.4 ± 7.9 kg m(-2)) with MO in comparison with 40 CO (mean age: 42 ± 13 years; mean BMI: 26.0 ± 5.5 kg m(-2)). All patients were investigated before and 2 years after bariatric surgery. Apart from weight and CV risk markers (blood pressure, lipids), a glucose tolerance test (75 g), renal and inflammation parameters were assessed. sRAGE levels were assessed by a commercial ELISA. To investigate the associations of the observed reductions of values, delta (Δ) of parameters were calculated. Patients with MO had significant lower sRAGE levels than CO: 1010 ± 514 vs 1501 ± 674 pg ml(-1); P<0.001. In the longitudinal study, sRAGE levels increased significantly after bariatric surgery from 1010 ± 514 to 1261 ± 710 pg ml(-1); P=0.008. In the correlation analysis, ΔsRAGE levels were associated with Δ1-h and Δ2-h postprandial glucose, Δfasting insulin, Δ2-h postprandial insulin, ΔHOMA (homeostatic model assessment)-insulin resistance (ΔHOMA-IR), Δγ-glutamyl transferase and Δtriglycerides. In a multivariate model, Δ1-h and Δ2-h postprandial glucose, Δ2-h postprandial insulin and ΔHOMA-IR predicted ΔsRAGE. Patients with MO have significantly lower sRAGE levels compared with non-obese CO, but sRAGE levels increase significantly after weight loss induced by bariatric surgery. As high sRAGE levels inhibit the activation of inflammatory pathways, our results might help understand the beneficial effects of bariatric surgery regarding CV morbidity and mortality.

Soluble receptor for advanced glycation end-product levels are related to albuminuria and arterial stiffness in essential hypertension

Background and aimsEmerging evidence suggests that the soluble receptor for advanced glycation end-products (sRAGE) is implicated in the development of vascular disease. We investigated the interrelationships of sRAGE with albumin to creatinine ratio (ACR) and arterial stiffness in essential hypertension. Methods and resultsIn 309 untreated non-diabetic hypertensives, ACR values were determined as the mean of three non-consecutive morning spot urine samples and aortic stiffness was evaluated on the basis of carotid to femoral pulse wave velocity (c-f PWV). In all subjects, venous blood sampling was performed for the estimation of sRAGE levels. Patients with low (n = 155) compared to those with high sRAGE values (n = 154) had greater 24-h systolic BP (140 ± 8 vs. 134 ± 7 mmHg, p < 0.0001), exhibited higher ACR (36.3 ± 51.6 vs. 17.2 ± 1.2 mg g−1, p < 0.0001) and c-f PWV (8.3 ± 1.5 vs. 7.8 ± 1.1 m s−1, p = 0.003), independently of confounding factors. Multiple regression analyses revealed that age, male sex, 24-h systolic BP and sRAGE were the ‘independent correlates’ of ACR (R2 = 0.493, p < 0.0001), while age, 24-h systolic BP and sRAGE were the ‘independent correlates’ of c-f PWV (R2 = 0.428, p < 0.0001). ConclusionIn hypertensives, decreased sRAGE levels are accompanied by pronounced albuminuria and arterial stiffening. The association of sRAGE with ACR and c-f PWV suggests involvement of sRAGE in the progression of hypertensive vascular damage.