key: cord-0687009-v4h6ptyp authors: Erusalimsky, Jorge D. title: The use of the soluble receptor for advanced glycation-end products (sRAGE) as a potential biomarker of disease risk and adverse outcomes date: 2021-03-29 journal: Redox Biol DOI: 10.1016/j.redox.2021.101958 sha: af90502139d4289a9e214dc655cbaa55b34e49c0 doc_id: 687009 cord_uid: v4h6ptyp The soluble receptor for advanced glycation end-products (sRAGE) has been classically considered a sink for pro-inflammatory RAGE ligands and as such has been associated with protection from inflammatory stress and disease. An alternative, though not mutually exclusive view is that high levels of sRAGE in circulation reflect the overstimulation of cell surface RAGE which if persistent, lead to the amplification of pro-inflammatory processes and the exacerbation of pathological states. With these two scenarios in mind this review focuses on the potential role of sRAGE as a prospective biomarker of disease risk and adverse outcomes. The receptor for advanced glycation end-products (RAGE) and its soluble forms -collectively known as sRAGE -are increasingly implicated in host defence from infections, inflammation, cardiometabolic disorders and age-related diseases [1] [2] [3] . Over the last twenty years hundreds of papers have described correlations between sRAGE levels and pathophysiological states or disease prognosis, but findings have been inconsistent [4, 5] . In this paper I review briefly the biology underlying the generation of sRAGE isoforms and the factors that modulate their levels in the circulation. Then, I discuss the potential functions of sRAGE molecules as well as their relationship with oxidative stress, to finally focus on the evidence supporting their potential use as a biomarker of disease risk and adverse outcomes. RAGE is a multiligand pattern recognition cell surface receptor belonging to the immunoglobulin superfamily [1] . Advanced glycation end-products (AGEs), which arise from the non-enzymatic glycation and oxidation of proteins, lipids and nucleic acids, were the first RAGE ligands to be described [6] , giving this receptor its name. Over the years following its discovery, it became increasingly recognized that RAGE binds also a variety of other ligands, including molecules derived from stressed or damaged cellse.g., amyloid β peptide, high-mobility group box 1 (HMGB1) and S100 proteinscollectively known as damage associated molecular patterns (DAMPs), cell adhesion moleculese.g. the β2 integrin MAC-1 -, and molecules originating from bacteria, viruses and parasites (reviewed in Refs. [1, 7] ). As such RAGE plays an important role in the innate immune response and as a mediator of pro-inflammatory processes. Upon ligand binding RAGE-mediated intracellular signalling (reviewed in Ref. [2] ) can lead to an increase in the production of reactive oxygen species (ROS) [8] [9] [10] and to the sustained activation of the transcription factor NFkB [11] . The latter stimulates the expression of pro-inflammatory modulators (e.g., IL1β, VCAM-1 and TNF-α) [12, 13] , and of RAGE itself [12] , thus providing a positive feedback mechanism to amplify the inflammatory response (see Fig. 1 ). RAGE is constitutively expressed at high levels in the lungs and skin of healthy adults [14, 15] , whereas expression in other tissues is either virtually absente.g. in skeletal muscle [16] or low -e.g. in cells of the cardiovascular, immune and central nervous systems (reviewed in Refs. [2, 16] ). However, in cardiometabolic, inflammatory or age-related diseases RAGE expression increases in different cell types [2, 16] , this upregulation being a direct consequence of an increase in ligand levels associated with these conditions [1] . Similarly, expression also increases in acute muscle injury [16] and during the host response to infection [3] . In addition to cell membrane-anchored RAGE, there are two major soluble forms of this receptor detected in blood and other body fluids, both of which lack its transmembrane and cytoplasmic domains [4] . These two RAGE isoforms are jointly known as soluble RAGE (sRAGE). One form of sRAGE, sometimes called cRAGE, is generated at the cell surface by the proteolytic cleavage of RAGE at the boundary between its extracellular and transmembrane portions [17, 18] . This RAGE ectodomain shedding is stimulated by inflammatory signals, including HMGB1 [18] , lipopolysaccharide [19] and TNF-α [19] . In addition, activation of G protein-coupled receptors [20] , intracellular calcium mobilization [21] and elevation of cAMP levels [22] have also been reported to promote this process. Two metalloproteases have been implicated in the generation of the cleaved form of sRAGE, MMP9 [17, 19] and ADAM10 [17] [18] [19] . MMP9 expression is known to be up-regulated by ROS and the activation of the RAS-ERK-NFkB pathway (reviewed in Ref. [23] ). Furthermore, TNF-α and RAGE overexpression can also increase MMP9 expression [19] . Similarly, TNF-α and RAGE overexpression can stimulate ADAM10 activation via an ATF4-dependent mechanism [19] . Taken together, these events are consistent with RAGE downstream signals promoting sRAGE shedding through an amplification mechanism involving auto-induction and/or induction of other inflammatory cytokines (Fig. 1) . The second form of sRAGE, called esRAGE (for endogenous secretory RAGE) or RAGEv1, results from alternative splicing of RAGE pre-mRNA [24, 25] and accounts for less than 25% of total circulating sRAGE [26] (Fig. 1 ). The precise mechanism which regulates the formation of esR-AGE is not entirely understood. The alternative splicing of RAGE pre-mRNA generates more than 20 splice variants, of which full length membrane-bound RAGE and esRAGE are the two most abundant [24] . The RAGE gene (AGER) has 11 exons. esRAGE is produced by inclusion of part of intron 9 with exon 9 and exclusion of exon 10. This results in a variant which has a reading frame shift at amino acid residue 332 and lacks the intracellular and transmembrane domains [24] . In neuroblastoma, human umbilical vein endothelial cells and HepG2 cells two splicing factors, namely heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) and Transformer 2β-1 (Tra2β-1), have been shown to regulate the ratio between full length RAGE and esRAGE by exerting antagonistic effects on the selection of alternative exons [27] . Furthermore, in neuroblastoma cells glucose deprivation induced an up-regulation of hnRNP A1 and down-regulation of Tra2β-1, resulting in a decrease in esRAGE expression and an in increase in the RAGE/esRAGE ratio [27] . These findings suggest that impaired glucose metabolism may be one factor affecting the regulation of esRAGE levels. sRAGE isoforms are highly stable [28] and can be measured from stored frozen serum or plasma samples using antibody-based ELISA assays. There are two types of assays. One assay detects total sRAGE, whereas the other measures specifically esRAGE. The latter uses an antibody directed against the unique COOH-terminal sequence of RAGE-v1 and does not cross-react with the cleaved form of sRAGE. esRAGE and sRAGE levels are strongly correlated [26, [29] [30] [31] and values in plasma and serum are quite comparable [28] . Average sRAGE concentrations in different studies generally fall within a similar range, although there is substantial variability between individuals [26, [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] . For example, in sera of 1228 European community dwelling older adults enrolled in the FRAILOMIC study, the median value of sRAGE was 1228 pg/ml with an interquartile range of 943-1638 pg/ml [41] . Importantly, sRAGE levels are invariably higher in people with diminished kidney function [26, 30, 42] and in some studies they also tend to be higher in diabetics [33, 43] . Part of the variability in blood levels of sRAGE is probably determined by genetic differences between individuals. AGER is a highly polymorphic gene [44] , with some variants affecting levels of both the cleaved form of sRAGE and esRAGE [30] . Furthermore, sRAGE levels may be influenced by polymorphisms in other genes, for example in ADAM10 [45] . Finally, levels of both sRAGE isoforms are strongly affected by ethnicity, being lower in people from Afro-Caribbean and Hispanic origin than in Caucasians [26, 30, 35] . Other studies in patients with cardiometabolic conditions have shown that the concentration of sRAGE isoforms in blood can be influenced by therapeutic agents, including angiotensin receptor blockers (ARBs), angiotensin converting enzyme inhibitors, calcium channel antagonists, statins and thiazolidinediones (reviewed in Ref. [4] ). ARBs were found to decrease sRAGE levels in angiotensin II-treated endothelial cells and in patients with essential hypertension [46] . Similarly, the calcium channel blocker azelnidipine was shown to reduce sRAGE in non-diabetic chronic nephropathy [47] . In contrast, statins and thiazolidinediones cause an increase in blood levels of both total sRAGE and esRAGE in type 2 diabetes [48] [49] [50] . Likewise, physical exercise has been reported to increase esRAGE levels in people at low/intermediate risk of cardiovascular disease (CVD) [51] . The detailed mechanisms underlying the different effects of these interventions are not known, though in the case of statins, these were reported to stimulate RAGE shedding by an ADAM10-mediated mechanism [52] . In addition, some of the drugs may affect sRAGE levels by inhibiting inflammation pathways [53] or by improving renal function [26, 42] . The function that sRAGE plays in human biology has been the subject of substantial debate. A widely held view is that sRAGE fulfills a Ligand binding to the extracellular domain initiates intracellular signalling, leading to the generation of ROS and to the activation of the transcription factor NFkB. The latter induces gene expression of pro-inflammatory cytokines such as TNF-α and of RAGE itself. RAGE downstream signalling events in turn promote the upregulation of MMP9 and ADAM10, which cleave membrane-bound RAGE, causing the release of its extracellular portion (cRAGE). ATF4 is linked to ADAM10 upregulation. cRAGE constitutes the majority of sRAGE. Alternative splicing of the RAGE gene (AGER) results in the generation of esRAGE, which also contributes to the sRAGE pool. A unique amino acid sequence in esRAGE (purple) distinguishes it from cRAGE. protective anti-inflammatory role by acting as a decoy receptor, binding RAGE ligands and thus blocking their interaction with membrane-bound RAGE. In support of this possibility experiments in animals models of diabetes and/or CVD have shown that administration of recombinant sRAGE improves vascular and renal function, reduces myocardial ischaemic injury, as well as atherosclerosis, vascular inflammation and other diabetic complications (Reviewed in Ref. [1] ). In addition, sRAGE administration has been shown to decrease inflammation in an animal model of multiple sclerosis [54] . In considering the function of sRAGE as a decoy receptor, it is relevant to note that in RAGE-deficient mice (Ager − /− ) sRAGE can still block certain inflammation responses, probably by preventing putative RAGE ligands from interacting with other receptors [55] . Aside from behaving as a decoy receptor sRAGE may also act as a ligand of the leukocyte integrin MAC-1 and transduce pro-inflammatory signals, thereby inducing leukocyte recruitment to sites of injury or inflammation [56, 57] . Consistent with this role, bacterial burden and neutrophil infiltration was shown to worsen following sRAGE administration in a mouse model of bacterial lung infection, suggesting that in acute settings sRAGE may actually sustain inflammation [58] . In contrast, sRAGE has been shown to prevent leukocyte recruitment in a diabetic mouse model of acute peritonitis [59] . sRAGE forms have been measured in humans in search for associations with disease states or their risk factors (reviewed in Refs. [60, 61] ). Many of these studies reported sRAGE levels to be lower in people with cardiometabolic and other chronic conditions than in healthy subjects, providing further support to the notion that sRAGE fulfills a protective role [60] . Nevertheless, positive associations between sRAGE levels and prevalent ill health have also been described, most notably in the contexts of diabetes and renal disease [60, 61] , and more recently also in frailty [62] . These contrasting lines of evidence suggest that the status of sRAGE in human pathophysiology deserves further examination. In this regard, an alternative view argues that the amount of sRAGE generated in vivo may not be sufficient to compete effectively with membrane-bound RAGE for ligand binding, particularly in situations where RAGE itself is also upregulated [2] . Furthermore, an increase in total circulating levels of sRAGE may reflect increased RAGE activation and autoinduction [18, 63] , and in this way attest to a condition of low-grade chronic inflammation, rather than to a healthy state. Several lines of evidence indicate that RAGE activation by AGEs and other ligands cause oxidative stress [8, 9, 64, 65] . Consistent with this notion and in keeping with the decoy receptor concept described above, sRAGE has been shown to reduce markers of oxidative stress when administered to animal models of vascular dysfunction [66, 67] . Hence, sRAGE is sometimes attributed an 'anti-oxidant role'. This view has been also supported by reports from small clinical studies of atherosclerotic vascular disease or cardiometabolic disorders describing inverse correlations between sRAGE levels and makers of oxidative stress [68] [69] [70] [71] [72] [73] , and by a study describing a positive correlation with plasma anti-oxidant defenses in Alzheimer's disease patients [74] . However, it should be noted that these types of associations are not universal. Thus for example in acute liver failure, both a protein oxidation marker and sRAGE levels were shown to be elevated [75] , whereas in patients with sickle cell disease an increase in sRAGE was positively correlated with an increase in the levels of ferritin, which in this condition is indicative of iron overload [76] . In addition, in a recent study of patients with type 2 diabetes, compared to non-diabetic controls both sRAGE levels and malondialdehyde were shown to be elevated, whereas antioxidant thiol levels were shown to be reduced [77] ; furthermore, this study reported that these differences were even more pronounced in individuals who had developed diabetic retinopathy [77] . Mechanistically, a ROS-induced up-regulation of MMP9 [23] , which in turn would result in an increase in RAGE ectodomain shedding, provides a reasonable explanation for these findings. Human interventional studies that examined sRAGE levels and markers of oxidative status, provide further insights into the relationship between these parameters in vivo. In master athletes a Mediterranean diet was shown to reduce both sRAGE and malondialdehyde [78] . Furthermore, in type 2 diabetes it was recently demonstrated that treatment with metformin for three months resulted in a reduction in sRAGE levels and oxidative stress markers, and also in an increase in antioxidant defenses [79] . Thus, taken together the above examples caution against considering a comparatively high level of sRAGE, a sign of low oxidative burden and/or good health. A variety of prospective studies have examined the relationship between sRAGE and the incidence of chronic diseases and/or the occurrence of adverse clinical outcomes. Table 1 summarizes examples of such studies in population samples of different health characteristics. For adults who in the main had no documented pre-existing chronic conditions at baseline, findings were mixed. In non-prescreened adults from the general population, positive [80] or no significant associations [40, 81] were generally reported, whereas for individuals with no prior history of CVD, the associations with incident disease or adverse events were found to be negative [38, 82, 83] . In contrast, studies carried out in diabetics (type I or type 2) consistently reported that high levels of sRAGE were predictive of cardiovascular events and/or mortality [26, 36, [84] [85] [86] . Similarly, other studies have shown that in individuals with pre-existing heart failure [31, 34, 37, 87] , coronary artery disease [39, 88] , frailty [41, 89] or physical disability [32] , high sRAGE levels were associated with a higher incidence of adverse cardiovascular events and/or mortality. On the other hand, absence of associations with adverse events, have also been described, including in patients with advanced chronic kidney disease [90, 91] , in another cohort of individuals with pre-existing heart failure [92] , and in a large cohort of people with chronic obstructive pulmonary disease and high cardiovascular risk [93] . Finally, a negative association between total sRAGE or esRAGE and mortality has been reported in cancer [29] . Taken together, these observational studies indicate that the relationship between total sRAGE (or esRAGE) and disease risk or the occurrence of adverse events, including mortality, is complex. Explanations for conflicting findings between different studies could be related to the demographic, genetic and health characteristics of the populations under investigation. In particular, the presence of frailty, diabetes and impaired kidney function may have a strong influence on these relationships [41, 61] . In addition, some studies could have been statistically underpowered to detect significant prospective associations or might have not accounted for potentially relevant confounders (e.g., renal function). In addition to its evaluation as a prognostic biomarker in chronic conditions, sRAGE has also been studied in acute settings. Consistent with the notion that RAGE is highly overexpressed in lung epithelium and that RAGE signalling may play a central role in the pathological manifestations of lung injury, elevated sRAGE levels, were found to predict 90-day mortality in patients suffering from acute respiratory distress syndrome [94] . Similarly, elevated sRAGE levels are associated with looming mortality in sepsis [95] and acute liver failure [75] , reflecting the prominent role that DAMPs play in RAGE activation in these conditions [3] . Although sRAGE has been studied as a marker of disease risk and adverse outcomes for many years, its potential prognostic value continues to be questioned due to the inconsistency in the directionality of the associations observed in different clinical settings. As a telltale footprint left from the sustained RAGE stimulation and the concomitant relentless cellular stress caused by an enduring inflammatory milieu, sRAGE may be a useful prognostic biomarker of irreversible loss of homeostasis and eventual mortality. As such sRAGE may not be useful for prognosis in the general "healthy" population. Instead, its clinical application may be more suited to multimorbid individuals or to those who have been afflicted by a chronic illness for a considerable length of time. Thus, for example, in the cardiovascular setting, elevated sRAGE levels have been recently shown to be highly predictive of mortality in patients who were also frail [41] . Similarly, in acute conditions a dramatic and sustained increase in sRAGE levels may be also a sign of impending irreversible organ damage and mortality, for example in acute lung injury/acute respiratory distress syndrome [96] . Theoretically, this could be relevant in respiratory viral illnesses such as Covid-19, where increased levels of DAMPs are associated with disease severity (reviewed in Ref. [97] ) and serum sRAGE appears to be raised [98] . In such contexts, determination of sRAGE levels could be useful for risk stratification and potentially, to inform clinical management, e.g., to select a course of treatment. In this respect, a clinically relevant threshold of sRAGE has so far not been established. Based on our own studies in frail older adults, we suggested that values of sRAGE in the range of 1600-1800 pg/ml might be relevant to set up a threshold which could be used for risk stratification [41, 89] . Nevertheless, further studies will be required to narrow down and validate this value, for this and other clinical conditions. In this respect, future studies should also aim to establish if following changes in sRAGE levels over time, could be used to ascertain if an individual is responding to a selected course of treatment. Part of the work described in this manuscript was supported by the European Union Seventh Framework Programme under grant agreement number 305483. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. ADAM10 disintegrin and metalloproteinase domain-containing protein 10 AGER advanced glycation end-products receptor gene AGEs advanced glycation end-products ATF4 activating transcription factor 4 HMGB1 high mobility group box 1 MAC-1 macrophage 1 antigen MMP9 matrix metalloprotease 9 NFkB nuclear factor kappa B ROS reactive oxygen species Table 1 Human observational studies exploring the association between sRAGE levels and incidence of chronic diseases or adverse outcomes. Mortality ↓* [29] Abbreviations: ACS, acute coronary syndromes; CAD, coronary artery disease; CIMT, carotid intima-media thickness; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; PVD, peripheral vascular disease; T1D, type 1 diabetes; T2D; type 2 diabetes. Age is indicated as median, mean or range. *also reported association with esRAGE. ↔, no significant association; ↑, positive significant association; ↓, negative significant association. Targeting RAGE signaling in inflammatory disease RAGE regulation and signaling in inflammation and beyond The role of RAGE in host pathology and crosstalk between RAGE and TLR4 in innate immune signal transduction pathways Soluble RAGEs -prospects for treating & tracking metabolic and inflammatory disease Is there any evidence that AGE/sRAGE is a universal biomarker/risk marker for diseases? Cloning and expression of a cell surface receptor for advanced glycosylation end products of proteins RAGE: a single receptor fits multiple ligands Activation of NADPH oxidase by AGE links oxidant stress to altered gene expression via RAGE Role of advanced glycation end products in cellular signaling Glycated proteins stimulate reactive oxygen species production in cardiac myocytes: involvement of Nox 2 (gp91phox)-containing NADPH oxidase Diabetes-associated sustained activation of the transcription factor nuclear factor-kappaB HMGB1 activates nuclear factor-kappaB signaling by RAGE and increases the production of TNFalpha in human umbilical vein endothelial cells RAGE mediates a novel proinflammatory axis: a central cell surface receptor for S100/calgranulin polypeptides Receptor for advanced glycation endproducts (RAGE) exhibits highly differential cellular and subcellular localisation in rat and human lung The receptor for advanced glycation end products is highly expressed in the skin and upregulated by advanced glycation end products and tumor necrosis factor-alpha RAGE in the pathophysiology of skeletal muscle Receptor for advanced glycation end products is subjected to protein ectodomain shedding by metalloproteinases A soluble form of the receptor for advanced glycation endproducts (RAGE) is produced by proteolytic cleavage of the membrane-bound form by the sheddase a disintegrin and metalloprotease 10 (ADAM10) JNK and ATF4 as two important platforms for tumor necrosis factor-alpha-stimulated shedding of receptor for advanced glycation end products Induction of RAGE shedding by activation of G protein-coupled receptors Calcium-regulated intramembrane proteolysis of the RAGE receptor cAMP ameliorates inflammation by modulation of macrophage receptor for advanced glycation end-products Matrix metalloproteinases in diabetic retinopathy: potential role of MMP-9 Identification, classification, and expression of RAGE gene splice variants Novel splice variants of the receptor for advanced glycation end-products expressed in human vascular endothelial cells and pericytes, and their putative roles in diabetes-induced vascular injury Total soluble and endogenous secretory receptor for advanced glycation end products as predictive biomarkers of coronary heart disease risk in patients with type 2 diabetes: an analysis from the CARDS trial Regulation of RAGE splicing by hnRNP A1 and Tra2beta-1 and its potential role in AD pathogenesis Methodological and preanalytical evaluation of a RAGE immunoassay Diminished levels of the soluble form of RAGE are related to poor survival in malignant melanoma Cross-sectional analysis of AGE-CML, sRAGE, and esRAGE with diabetes and cardiometabolic risk factors in a community-based cohort The different roles for the advanced glycation end products axis in heart failure and acute coronary syndrome settings Advanced glycation end products and their circulating receptors predict cardiovascular disease mortality in older community-dwelling women Increased serum concentrations of soluble receptor for advanced glycation endproducts in patients with type 1 diabetes Soluble Receptor for advanced glycation end products (RAGE) is a prognostic factor for heart failure Association of serum soluble receptor for advanced glycation end-products with subclinical cerebrovascular disease: the Northern Manhattan Study (NOMAS) Soluble receptor for AGE (RAGE) is a novel independent predictor of all-cause and cardiovascular mortality in type 1 diabetes Relation of soluble receptor for advanced glycation end products to predict mortality in patients with chronic heart failure independently of Seattle Heart Failure Score Astor, sRAGE and risk of diabetes, cardiovascular disease, and death Prediction of cardiovascular events in statin-treated stable coronary patients of the treating to new targets randomized controlled trial by lipid and non-lipid biomarkers Association between advanced glycation end products, their soluble receptor, and mortality in the general population: results from the CARLA study Higher sRAGE levels predict mortality in frail older adults with cardiovascular disease Advanced glycation end products and their circulating receptors and level of kidney function in older community-dwelling women Elevation of soluble form of receptor for advanced glycation end products (sRAGE) in diabetic subjects with coronary artery disease Pathological implications of receptor for advanced glycation end-product (AGER) gene polymorphism Influence of ADAM10 polymorphisms on plasma level of soluble receptor for advanced glycation end products and the association with alzheimer's disease risk Telmisartan inhibits expression of a receptor for advanced glycation end products (RAGE) in angiotensin-II-exposed endothelial cells and decreases serum levels of soluble RAGE in patients with essential hypertension Calcium channel blocker inhibition of AGE and RAGE axis limits renal injury in nondiabetic patients with stage I or II chronic kidney disease Effects of atorvastatin on serum soluble receptors for advanced glycation end-products in type 2 diabetes Comparison of effects of pioglitazone and glimepiride on plasma soluble RAGE and RAGE expression in peripheral mononuclear cells in type 2 diabetes: randomized controlled trial (PioRAGE) Thiazolidinedione increases serum soluble receptor for advanced glycation end-products in type 2 diabetes Effects of high-amount-high-intensity exercise on in vivo platelet activation: modulation by lipid peroxidation and AGE/RAGE axis Statins stimulate the production of a soluble form of the receptor for advanced glycation end products Allisartan isoproxil attenuates oxidative stress and inflammation through the SIRT1/Nrf 2/NFkappaB signalling pathway in diabetic cardiomyopathy rats Suppression of experimental autoimmune encephalomyelitis by selective blockade of encephalitogenic T-cell infiltration of the central nervous system Receptor for advanced glycation end products (RAGE) regulates sepsis but not the adaptive immune response Soluble receptor for advanced glycation end products triggers a proinflammatory cytokine cascade via beta 2 integrin Mac-1 Marsh, sRAGE induces human monocyte survival and differentiation The shedding-derived soluble receptor for advanced glycation endproducts sustains inflammation during acute Pseudomonas aeruginosa lung infection The pattern recognition receptor (RAGE) is a counterreceptor for leukocyte integrins: a novel pathway for inflammatory cell recruitment Emerging targets for therapeutic development in diabetes and its complications: the RAGE signaling pathway Low levels of serum soluble receptors for advanced glycation end products, biomarkers for disease state: myth or reality A robust machine learning framework to identify signatures for frailty: a nested case-control study in four aging Serum levels of sRAGE, the soluble form of receptor for advanced glycation end products, are associated with inflammatory markers in patients with type 2 diabetes RAGE ligands induce apoptotic cell death of pancreatic β-cells via oxidative stress Receptor for advanced glycation end products activation injures primary sensory neurons via oxidative stress Activation of receptor for advanced glycation end products contributes to aortic remodeling and endothelial dysfunction in sinoaortic denervated rats Soluble receptor for advanced glycation end products mitigates vascular dysfunction in spontaneously hypertensive rats Soluble RAGE in type 2 diabetes: association with oxidative stress, Free Radic Decreased plasma soluble RAGE in patients with hypercholesterolemia: effects of statins, Free Radic Correlation of the plasma levels of soluble RAGE and endogenous secretory RAGE with oxidative stress in pre-diabetic patients Atherosclerosis and the hypercholesterolemic AGE-RAGE Axis Advanced glycation end products: receptors for advanced glycation end products Axis in coronary stent restenosis: a prospective study Could AGE/RAGE-Related oxidative homeostasis dysregulation enhance susceptibility to pathogenesis of cardio-metabolic complications in childhood obesity? Lag-time in Alzheimer's disease patients: a potential plasmatic oxidative stress marker associated with ApoE 4 isoform Biomarkers of oxidation stress, inflammation, necrosis and apoptosis are associated with hepatitis B-related acuteon-chronic liver failure Soluble receptor for advanced glycation end products as a vasculopathy biomarker in sickle cell disease Plasma angiogenesis and oxidative stress markers in patients with diabetic retinopathy Curcumin and boswellia serrata modulate the glyco-oxidative status and lipo-oxidation in master athletes Action of metformin therapy against advanced glycation, oxidative stress and inflammation in type 2 diabetes patients: 3 months follow-up study Protein biomarkers of cardiovascular disease and mortality in the community Assessment of advanced glycation end products and receptors and the risk of dementia Soluble receptor for advanced glycation end products and the risk for incident heart failure: the Atherosclerosis Risk in Communities Study High plasma sRAGE (soluble receptor for advanced glycation end products) is associated with slower carotid intimamedia thickness progression and lower risk for first-time coronary events and mortality Higher plasma soluble Receptor for Advanced Glycation End Products (sRAGE) levels are associated with incident cardiovascular disease and all-cause mortality in type 1 diabetes: a 12-year followup study Circulating soluble RAGE as a predictive biomarker of cardiovascular event risk in patients with type 2 diabetes Relationship between levels of advanced glycation end products and their soluble receptor and adverse outcomes in adults with type 2 diabetes Clinical use of high mobility group box 1 and the receptor for advanced glycation end products in the prognosis and risk stratification of heart failure: a literature review Soluble form of receptor for advanced glycation end products and incidence of new cardiovascular events among patients with cardiovascular disease Increased levels of soluble Receptor for Advanced Glycation End-products (RAGE) are associated with a higher risk of mortality in frail older adults Effect of circulating soluble receptor for advanced glycation end products (sRAGE) and the proinflammatory RAGE ligand (EN-RAGE, S100A12) on mortality in hemodialysis patients Associations between soluble receptor for advanced glycation end products (sRAGE) and S100A12 (EN-RAGE) with mortality in long-term hemodialysis patients The role of advanced glycation end-products and their receptor on outcome in heart failure patients with preserved and reduced ejection fraction Serum biomarkers and outcomes in patients with moderate COPD: a substudy of the randomised SUMMIT trial Plasma sRAGE is independently associated with increased mortality in ARDS: a meta-analysis of individual patient data Soluble receptor for advanced glycation end products predicts 28-day mortality in critically ill patients with sepsis, Scand Plasma receptor for advanced glycation end products and clinical outcomes in acute lung injury Journey to a receptor for advanced glycation end products connection in severe acute respiratory syndrome coronavirus 2 infection 41 Soluble receptor for advanced glycation end products and its forms in COVID-19 patients with and without diabetes mellitus: a pilot study on their role as disease biomarkers