Effects of novel polymorphisms in the RAGE gene on transcriptional regulation and their association with diabetic retinopathy

Receptor for advanced glycation end products polymorphisms in coronary artery ectasia

BACKGROUND

Although the implication of receptor of advanced glycation endproducts (RAGE) has been reported in coronary artery disease, its roles in coronary artery ectasia (CAE) have remained undetermined. Furthermore, the effect of RAGE polymorfisms were not well-defined in scope of soluble RAGE (sRAGE) levels. Thus, we aimed to investigate the influence of the functional polymorphisms of RAGE -374T > A (rs1800624) and G82S (rs2070600) in CAE development.

METHODS

This prospective observational study was conducted in 2 groups selected of 2452 patients who underwent elective coronary angiography (CAG) for evaluation after positive noninvasive heart tests. Group-I included 98 patients with non-obstructive coronary artery disease and CAE, and Group-II (control) included 100 patients with normal coronary arteries. SNPs were genotyped by real-time PCR using Taqman® genotyping assay. Serum sRAGE and soluble lectin-like oxidized receptor-1 (sOLR1) were assayed by ELISA and serum lipids were measured enzymatically.

RESULTS

The frequencies of the RAGE -374A allele and -374AA genotype were significantly higher in CAE patients compared to controls (p < 0.001). sRAGE levels were not different between study groups, while sOLR1 levels were elevated in CAE (p = 0.004). In controls without systemic disease, -374A allele was associated with low sRAGE levels (p < 0.05), but this association was not significant in controls with HT. Similarly, sRAGE levels of CAE patients with both HT and T2DM were higher than those no systemic disease (p = 0.02). The -374A allele was also associated with younger patient age and higher platelet count in the CAE group in both total and subgroup analyses. In the correlation analyses, the -374A allele was also negatively correlated with age and positively correlated with Plt in all of these CAE groups. In the total CAE group, sRAGE levels also showed a positive correlation with age and a negative correlation with HDL-cholesterol levels. On the other hand, a negative correlation was observed between sRAGE and Plt in the total, hypertensive and no systemic disease control subgroups. Multivariate logistic regression analysis confirmed that the -374A allele (p < 0.001), hyperlipidemia (p < 0.05), and high sOLR1 level (p < 0.05) are risk factors for CAE. ROC curve analysis shows that RAGE -374A allele has AUC of 0.713 (sensitivity: 83.7 %, specificity: 59.0 %), which is higher than HLD (sensitivity: 59.2 %, specificity: 69.0 %), HT (sensitivity: 62.4 %, specificity: 61.1 %) and high sOLR1 level (≥0.67 ng/ml)) (sensitivity: 59.8 %, specificity: 58.5 %).

CONCLUSION

Beside the demonstration of the relationship between -374A allele and increased risk of CAE for the first time, our results indicate that antihypertensive and antidiabetic treatment in CAE patients causes an increase in sRAGE levels. The lack of an association between the expected -374A allele and low sRAGE levels in total CAE group was attributed to the high proportion of hypertensive patients and hence to antihypertensive treatment. Moreover, the RAGE -374A allele is associated with younger age at CAE and higher Plt, suggesting that -374A may also be associated with platelet activation, which plays a role in the pathogenesis of CAE. However, our data need to be confirmed in a large study for definitive conclusions.

The RAGE Axis: A Relevant Inflammatory Hub in Human Diseases

In 1992, a transcendental report suggested that the receptor of advanced glycation end-products (RAGE) functions as a cell surface receptor for a wide and diverse group of compounds, commonly referred to as advanced glycation end-products (AGEs), resulting from the non-enzymatic glycation of lipids and proteins in response to hyperglycemia. The interaction of these compounds with RAGE represents an essential element in triggering the cellular response to proteins or lipids that become glycated. Although initially demonstrated for diabetes complications, a growing body of evidence clearly supports RAGE's role in human diseases. Moreover, the recognizing capacities of this receptor have been extended to a plethora of structurally diverse ligands. As a result, it has been acknowledged as a pattern recognition receptor (PRR) and functionally categorized as the RAGE axis. The ligation to RAGE leads the initiation of a complex signaling cascade and thus triggering crucial cellular events in the pathophysiology of many human diseases. In the present review, we intend to summarize basic features of the RAGE axis biology as well as its contribution to some relevant human diseases such as metabolic diseases, neurodegenerative, cardiovascular, autoimmune, and chronic airways diseases, and cancer as a result of exposure to AGEs, as well as many other ligands.

A correlation between oxidative stress and diabetic retinopathy: An updated review

Oxidative stress (OS) is a cytopathic outcome of excessively generated reactive oxygen species (ROS), down regulated antioxidant defense signaling pathways, and the imbalance between the produced radicals and their clearance. It plays a role in the genesis of several illnesses, especially hyperglycemia and its effects. Diabetic retinal illness, a micro vascular side effect of the condition, is the prime reason of diabetic related blindness. The OS (directly or indirectly) is associated with diabetic retinopathy (DR) and related consequences. The OS is responsible to induce and interfere the metabolic signaling pathways to enhance influx of the polyol cascades and hexosamine pathways, stimulate Protein Kinase-C (PKC) variants, and accumulate advanced glycation end products (AGEs). Additionally, the inequity between the scavenging and generation of ROS is caused by the epigenetic alteration caused by hyperglycemia that suppresses the antioxidant defense system. Induced by an excessive buildup of ROS, retinal changes in structure and function include mitochondrial damage, cellular death, inflammation, and lipid peroxidation. Therefore, it is crucial to comprehend and clarify the mechanisms connected to oxidative stress that underlie the development of DR.

The role of sRAGE in cardiovascular diseases

Advanced glycation end products (AGEs), by-products of glucose metabolism, have been linked to the emergence of cardiovascular disorders (CVD). AGEs can cause tissue damage in four different ways: (1) by altering protein function, (2) by crosslinking proteins, which makes tissue stiffer, (3) by causing the generation of free radicals, and (4) by activating an inflammatory response after binding particular AGE receptors, such as the receptor for advanced glycation end products (RAGE). It is suggested that the soluble form of RAGE (sRAGE) blocks ligand-mediated pro-inflammatory and oxidant activities by serving as a decoy. Therefore, several studies have investigated the possible anti-inflammatory and anti-oxidant characteristics of sRAGE, which may help lower the risk of CVD. According to the results of various studies, the relationship between circulating sRAGE, cRAGE, and esRAGE and CVD is inconsistent. To establish the potential function of sRAGE as a therapeutic target in the treatment of cardiovascular illnesses, additional studies are required to better understand the relationship between sRAGE and CVD. In this review, we explored the potential function of sRAGE in different CVD, highlighting unanswered concerns and outlining the possibilities for further investigation.

Nanopore Sequencing of RAGE Gene Polymorphisms and Their Association with Type 2 Diabetes

The receptor for advanced glycation end products (RAGE) is a transmembrane protein that interacts with its ligands, advanced glycation end products (AGEs). AGEs are elevated in diabetes and diabetic complications, leading to increased oxidative stress and activation of pro-inflammatory pathways facilitated by AGE-RAGE signaling. Polymorphisms in the RAGE gene can potentially affect AGE-RAGE interaction and its downstream signaling, which plays a crucial role in the progression of diabetes and its complications. In this study, we used nanopore sequencing for genotyping of RAGE polymorphism and identified a maximum number of 33 polymorphisms, including two previously unreported novel mutations in a cohort of healthy, type 2 diabetics without nephropathy and type 2 diabetics with nephropathy in order to identify associations. Two novel RAGE polymorphisms in the intron 8 and 3'UTR region at genomic locations 32181834 and 32181132, respectively, were detected with a low frequency. For four previously reported polymorphisms, cross-validation by PCR-RFLP showed 99.75% concordance with nanopore sequencing. Analysis of genotype distribution and allele frequencies revealed that five single nucleotide polymorphisms, i.e., rs1800625, rs3131300, rs3134940, rs2070600, and rs9391855, were associated with an increased risk for type 2 diabetes.

Polymorphisms −374 T/A and −429 T/C of the Receptor for Advanced Glycation End-Products (RAGE) and Serum Levels of RAGE (sRAGE) Are Not Associated with Metabolic Syndrome

RAGE is a multi-ligand transmembrane glycoprotein that promotes biological signals associated with inflammatory responses and degenerative diseases. sRAGE is a soluble variant, proposed as an inhibitor of RAGE activity. −374 T/A and −429 T/C polymorphisms of the advanced glycation end products receptor AGER gene are associated with the development of some diseases, such as type of cancer, cardiovascular disease, and micro and macrovascular disease in diabetes among others but their role in metabolic syndrome (MS) is still unknown. We studied 80 healthy men without MS, and 80 men with MS according to the harmonized criteria. −374 T/A and −429 T/C polymorphisms were genotyped by RT-PCR, and sRAGE was measured by ELISA. Allelic and genotypic frequencies did not differ between Non-MS and MS groups (−374 T/A p = 0.48, p = 0.57 and −429 T/C p = 0.36, p = 0.59). Significant differences were found in fasting glucose levels and diastolic blood pressure among the genotypes of the −374 T/A polymorphism in the Non-MS group (p < 0.01 and p = 0.008). Glucose levels were different between −429 T/C genotypes in the MS group (p = 0.02). sRAGE levels were similar in both groups, but in the Non-MS group showed a significant difference between individuals with only 1 or 2 components of the metabolic syndrome (p = 0.047). However, no associations of any SNP with MS were found (recessive model p = 0.48, dominant model p = 0.82 for −374 T/A; recessive model p = 0.48, dominant model p = 0.42 for −429 T/C). −374 T/A and −429 T/C polymorphisms are not associated with MS in Mexican population and have no influence on serum sRAGE levels.

The Potential Influence of Advanced Glycation End Products and (s)RAGE in Rheumatic Diseases

Advanced glycation end products (AGEs) are a class of compounds formed by nonenzymatic interactions between reducing sugars and proteins, lipids, or nucleic acids. AGEs can alter the protein structure and activate one of their receptors, specifically the receptor for advanced glycation end products (RAGE). These phenomena impair the functions of cells, extracellular matrix, and tissues. RAGE is expressed by a variety of cells and has been linked to chronic inflammatory autoimmune disorders such as rheumatoid arthritis, systemic lupus erythematosus, and Sjögren's syndrome. The soluble (s)RAGE cleavage product is a positively charged 48-kDa cleavage product that retains the ligand binding site but loses the transmembrane and signaling domains. By acting as a decoy, this soluble receptor inhibits the pro-inflammatory processes mediated by RAGE and its ligands. In the present review, we will give an overview of the role of AGEs, sRAGE, and RAGE polymorphisms in several rheumatic diseases. AGE overproduction may play a role in the pathogenesis and is linked to accelerated atherosclerosis. Low serum sRAGE concentrations are linked to an increased cardiovascular risk profile and a poor prognosis. Some RAGE polymorphisms may be associated with increased disease susceptibility. Finally, sRAGE levels can be used to track disease progression.

Determination of the effects of advanced glycation end products receptor polymorphisms and its activation on structural cell responses and inflammation in asthma

BACKGROUND

Advanced glycation end products receptor (RAGE) is a pattern recognition receptor which attracted attention in chronic airway diseases recently. This study aimed to determine the association of RAGE with asthma and the cellular responses resulting from RAGE signaling pathway activation.

METHODS

Asthmatic (n = 362) and healthy (n = 134) children were genotyped by PCR-RFLP. Plasma sRAGE levels were determined by ELISA. Lung structural cells were stimulated with AGEs (advanced glycation end products) and control BSA. Expressions of cytokines and protein levels were determined by real-time PCR and ELISA.

RESULTS

: Gly82Ser and -374 T/A polymorphisms in RAGE gene were associated with lower plasma sRAGE levels (p < 0.001 and p < 0.025, respectively). AGE stimulation increased the expression of RAGE (p = 0.002), ICAM-1 (p = 0.010) and VCAM-1 (p = 0.002) in endothelial cells; TIMP-1 (p = 0.003) and MCP-1 (p = 0.005) in fibroblasts. AGE stimulation increased protein levels of IL-6 (p < 0.001) in endothelial cells; VEGF (p = 0.025) and IL-8 (p < 0.001) in fibroblasts; IL-1b (p < 0.001) and VEGF (p = 0.007) in epithelial cells.

DISCUSSION

Activation of RAGE pathway may contribute to asthma pathogenesis by increasing the expression of several asthmarelated genes. These findings suggest that suppression of RAGE signaling may be an alternative candidate for treating asthma.

Aging Effects on Optic Nerve Neurodegeneration

Common risk factors for many ocular pathologies involve non-pathologic, age-related damage to the optic nerve. Understanding the mechanisms of age-related changes can facilitate targeted treatments for ocular pathologies that arise at any point in life. In this review, we examine these age-related, neurodegenerative changes in the optic nerve, contextualize these changes from the anatomic to the molecular level, and appreciate their relationship with ocular pathophysiology. From simple structural and mechanical changes at the optic nerve head (ONH), to epigenetic and biochemical alterations of tissue and the environment, multiple age-dependent mechanisms drive extracellular matrix (ECM) remodeling, retinal ganglion cell (RGC) loss, and lowered regenerative ability of respective axons. In conjunction, aging decreases the ability of myelin to preserve maximal conductivity, even with "successfully" regenerated axons. Glial cells, however, regeneratively overcompensate and result in a microenvironment that promotes RGC axonal death. Better elucidating optic nerve neurodegeneration remains of interest, specifically investigating human ECM, RGCs, axons, oligodendrocytes, and astrocytes; clarifying the exact processes of aged ocular connective tissue alterations and their ultrastructural impacts; and developing novel technologies and pharmacotherapies that target known genetic, biochemical, matrisome, and neuroinflammatory markers. Management models should account for age-related changes when addressing glaucoma, diabetic retinopathy, and other blinding diseases.

ITGA2 Gene Polymorphism Is Associated with Type 2 Diabetes Mellitus in the Kazakhstan Population

Background and Objectives: Nowadays, every tenth adult in the world suffers from diabetes mellitus (DM). Diabetic retinopathy (DR) is the most common microvascular complication of type 2 DM (T2DM) and a leading cause of acquired blindness in middle-aged individuals in many countries. Previous studies have identified associations of several gene polymorphisms with susceptibility to microvascular complications of DM in various worldwide populations. In our study, we aimed to test the hypothesis of the associations of single nucleotide polymorphisms (SNP) of the VEGF (−2549I/D), RAGE (−429T/C and −374T/A), TCF7L2 (rs7903146), and ITGA2 (BglII) genes with a predisposition to DR among T2DM patients in the Kazakhstan population. Materials and Methods: We conducted a case–control study comparing the genotype distribution and allele frequencies between groups of DR patients (N = 94), diabetic patients without DR (N = 94), and healthy controls (N = 51). Genotypes were identified using the PCR-RFLP method. Results: In all cases, the genotype distribution corresponded to the Hardy–Weinberg equilibrium. The groups of diabetic patients with and without DR did not significantly differ in the genotype distribution of the SNPs studied. Differences between both groups of diabetic patients and healthy controls in four out of five SNPs were also not significant. At the same time, both groups of diabetic patients differed significantly from healthy controls in genotype distribution (p = 0.042 and 0.005, respectively) and allele frequencies (p = 0.021 and 0.002, respectively) of the BglII polymorphism in the ITGA2 gene. After adjusting for multiple comparisons, the differences between the group of diabetic patients without DR and the control group remained significant (pBonf = 0.027 for genotypes and pBonf = 0.009 for alleles). The BglII− allele was associated with diabetes: OR = 1.81 [1.09–2.99] for DR patients, and OR = 2.24 [1.34–3.75] for diabetic patients without DR. The association was also observed in the subset of Kazakhs. Conclusions: This study shows that the BglII polymorphism in the ITGA2 gene can be associated with T2DM but not with DR. According to our data, the risk allele for diabetes is the wild BglII− allele, and not the minor BglII+, which is considered as risky for DR.

Role of RAGE in the Pathogenesis of Neurological Disorders

This review reflects upon our own as well as other investigators' studies on the role of receptor for advanced glycation end-products (RAGE), bringing up the latest information on RAGE in physiology and pathology of the nervous system. Over the last ten years, major progress has been made in uncovering many of RAGE-ligand interactions and signaling pathways in nervous tissue; however, the translation of these discoveries into clinical practice has not come to fruition yet. This is likely, in part to be the result of our incomplete understanding of this crucial signaling pathway. Clinical trials examining the therapeutic efficacy of blocking RAGE-external ligand interactions by genetically engineered soluble RAGE or an endogenous RAGE antagonist, has not stood up to its promise; however, other trials with different blocking agents are being considered with hope for therapeutic success in diseases of the nervous system.

Pathophysiology of RAGE in inflammatory diseases

The receptor for advanced glycation end products (RAGE) is a non-specific multi-ligand pattern recognition receptor capable of binding to a range of structurally diverse ligands, expressed on a variety of cell types, and performing different functions. The ligand-RAGE axis can trigger a range of signaling events that are associated with diabetes and its complications, neurological disorders, cancer, inflammation and other diseases. Since RAGE is involved in the pathophysiological processes of many diseases, targeting RAGE may be an effective strategy to block RAGE signaling.

Receptor of advanced glycation end product (RAGE) polymorphism and oxidative status in Hashimoto’s thyroiditis in Egyptian female patients: case control study

Background

Hashimoto's thyroiditis is the most widespread autoimmune illness targeting a specific organ. "Redox homeostasis" is achieved when the production of Reactive Oxygen Species and their elimination are in balance. Advanced glycation end products (AGEs) are formed when glucose and/or α-oxaloaldehydes react non-enzymatically with the amino groups of lipids, proteins, and DNA. Nowadays, many studies are concerned with AGEs, the polymorphisms of their receptors, and their association with increased risk of HT. However, few studies investigated the role of receptors of advanced glycation end product (RAGE) SNP in Egyptian females.

Objective

The goals of this investigation were to ascertain whether oxidative stress plasma malondialdehyde (MDA) and total antioxidant capacity (TAC) were associated with HT, in addition, to assess the association of RAGE polymorphisms (− 374 T > A and the − 429 T > C and Gly82Ser) with HT.

Subject and methods.

Our case–control study has 80 patients enrolled who have newly been diagnosed with HT and 80 age and sex-matched healthy female controls. Each participant underwent a thorough medical history, physical examination, and laboratory investigations, which included Genotyping of RAGE Gly82Ser, − 374 T > A and − 429 T > C using polymerase chain reaction-restriction fragment length polymorphisms (PCR–RFLP).

Results

Chi-square revealed a significant association regarding the distribution of RAGE (− 374 T < C) genotypes TT and CC between patients and control (P = 0.04). Non-significant associations regarding the distribution of Gly82Ser genotypes Gly/Gly, Gly/Ser, Ser/Ser were found between patients and control (P = 0.5), and non-significant associations related to − 429 T > C gene polymorphism were revealed. In addition, patients with HT had higher MDA and lower TCA compared with controls.

Conclusion

The elevated MDA and decreased TAC as an antioxidant may be one of several risk factors associated with the prevalence of HT in individuals with the − 429 T > C RAGE mutation polymorphism that is associated with an increased risk of HT in Egyptian females.

Single nucleotide variants of receptor for advanced glycation end-products (AGER) gene: is it a new opening in the risk assessment of diabetic retinopathy?-a review

BACKGROUND

Diabetic retinopathy (DR) is a common microvascular complication of diabetes. There is strong evidence suggesting that DR has an inheritable component. The interaction between advanced glycation end products (AGEs) and their receptor is integral in the pathogenesis of diabetic retinopathy and its various complications, retinopathy being one of them.

OVERVIEW AND METHODOLOGY

This review discusses the existing literature on the association between single nucleotide variants (SNV) of AGER gene and the risk of DR. It also discusses the current understanding of the AGE-AGER pathway in diabetic retinopathy. Through our article we have tried to consolidate all the available information about these SNVs associated with diabetic retinopathy in a succinct tabular form. Additionally, a current understanding of the AGE-AGER interaction and its deleterious effects on the cells of the retina has been discussed in detail to provide comprehensive information about the topic to the reader. A literature review was performed on PubMed, Cochrane Library, and Google Scholar for studies to find existing literature on the association between AGER gene SNVs and the risk, progression and severity of developing DR. This article will encourage scientific communication and discussion about possibly devising genetic markers for an important cause of blindness both in developed and developing countries, i.e., diabetic retinopathy.

RESULT

Based on genetic studies done in Indian and Chinese population G82S(rs2070600) was positively associated with Diabetic Retinopathy. Patients of diabetic retinopathy in Caucasian population had -T374A(rs1800624) polymorphism. + 20T/A was found to be associated with the disease in a study done in UK. Association with G1704T(rs184003) was seen in Chinese and Malaysian population. A Chinese study found its association with CYB242T. -T429C(rs1800625) SNV was not associated with DR in any of the studies. G2245A(rs55640627) was positively associated with the disease process in Malaysian population. It was not associated in Malaysian and Chinese population. Promoter variant rs1051993 has also been found to a susceptible SNV in the Chinese population.

CONCLUSION

While providing a comprehensive review of the existing information, we would like to emphasize on a large, multi-centric, trial with a much larger and varied population base to definitely determine these single nucleotide variants predisposing diabetic individuals.

AGER gene variant as a risk factor for juvenile idiopathic arthritis

BACKGROUND

The AGER gene encodes a cell surface multiligand receptor of advanced glycation end-products that is also capable of binding other molecules and is involved in numerous pathways related to inflammation, apoptosis, immunity and so on. In the present study, we aimed to investigate whether the AGER rs1035798 (G>A) intronic polymorphism, showing an association with multiple sclerosis and rheumatoid arthritis in adults, is related to juvenile idiopathic arthritis (JIA).

METHODS

Caucasian children from the Belarusian population were enrolled in the study. In total, there were 201 cases with JIA, 37 with juvenile systemic lupus erythematosus, 222 children with the articular syndrome of non-autoimmune etiology (positive control for JIA) and 365 negative controls (children without any autoimmune or inflammatory diseases). Genomic DNA samples from the patients and controls were genotyped by a real-time polymerase chain reaction.

RESULTS

A marked association of the homozygous AA rs1035798 genotype with JIA (p = 5 × 10^-4 ) was found. Allele A was also associated with JIA (p = 0.0058), as well as with the articular syndrome of non-autoimmune etiology (p = 0.0264). The highest frequencies of the AA genotype were found in the subgroups of JIA patients with polyarthritis or severe oligoarthritis. The AA genotype patients also had the smallest mean age of the JIA onset.

CONCLUSIONS

Our results demonstrate that the AGER rs1035798 AA genotype is a risk factor for JIA in Belarusian children. They also suggest a link between the AGER AA genotype and the risk of JIA early onset and severity. However, the functional relevance of the rs1035798 polymorphism is still unclear.

Development of a Method for Quantitation of Glyceraldehyde in Various Body Compartments of Rodents and Humans

There is limited information available about the physiological content of glyceraldehyde, a precursor of toxic advanced glycation end products. The conventional derivatization method for aldoses using 1-phenyl-3-methyl-5-pyrazolone did not allow reproducible quantification of glyceraldehyde due to the instability of glyceraldehyde compared to other aldoses. We optimized the derivatization condition to achieve high and reproducible recovery of derivatives for liquid chromatography tandem mass spectrometry quantification. Based on the stability of glyceraldehyde during sample preparation and high recovery of spiked standard, the present method provides reproducible quantification of glyceraldehyde in the body. The glyceraldehyde contents in fasting conditions in the rodent liver (mice: 50.0 ± 3.9 nmol/g; rats: 35.5 ± 4.9 nmol/g) were higher than those in plasma (9.4 ± 1.7 and 7.2 ± 1.2 nmol/mL). The liver glyceraldehyde levels significantly increased after food consumption (p < 0.05) but remained constant in the plasma. High fat diet feeding significantly increased plasma glyceraldehyde levels in mice (p < 0.005). In healthy human volunteers, the plasma glyceraldehyde levels remained unchanged after the consumption of steamed rice. In patients with type 2 diabetes, the plasma glyceraldehyde level was positively correlated with the plasma glucose level (r = 0.84; p < 0.0001).

The impact of receptor of advanced glycation end-products polymorphisms on prostate cancer progression and clinicopathological characteristics

The receptor for advanced glycation end products (RAGE) overexpression was suggested to be associated with prostate cancer development and poor prognosis. In this study, we focused on the correlations between the clinicopathological characteristics and susceptibility of prostate cancer and RAGE single-nucleotide polymorphisms (SNPs). In 579 prostate cancer patients, the RAGE SNPs rs1800625, rs1800624, rs2070600 and rs184003 in patients with or without grade group upgrade were analysed with real-time polymerase chain reaction. The results demonstrated that the prostate cancer patients who carried the RAGE SNPs rs2070600 'GA' genotypic variants were significantly associated with lower risk to develop grade group upgrade. Moreover, patients with the RAGE rs1800625 'TC + CC' genotypic variants were associated with higher risk of perineural invasion. In 343 prostate cancer patients who carried the RAGE rs1800625 'TC + CC' genotype without grade group upgrade were correlated with higher risk of biochemical recurrence and perineural invasion. In the analysis of TCGA database, significant differences of the RAGE mRNA level were found between the normal controls and prostate cancer patients (p < 0.0001), and the pathologic stage N1 and N0 patients (p = 0.0027). The prostate cancer patients with high RAGE expression were associated with lower overall survival rate (p = 0.025). In conclusion, our results have revealed that the RAGE SNPs rs2070600 and rs1800625 were associated with the grade group upgrade of prostate cancer and clinical status. The RAGE polymorphisms may provide as a pivotal predictor to evaluate prostate cancer disease progression and prognosis.

GRB10 rs1800504 Polymorphism Is Associated With the Risk of Coronary Heart Disease in Patients With Type 2 Diabetes Mellitus

Diabetic vascular complications are one of the main causes of death and disability. Previous studies have reported that genetic variation is associated with diabetic vascular complications. In this study, we aimed to investigate the association between GRB10 polymorphisms and susceptibility to type 2 diabetes mellitus (T2DM) vascular complications. Eight single nucleotide polymorphisms (SNPs) in the GRB10 gene were genotyped by MassARRAY system and 934 patients with type 2 diabetes mellitus (T2DM) were included for investigation. We found that GRB10 rs1800504 CC+CT genotypes were significantly associated with increased risk of coronary heart disease (CHD) compared with TT genotype (OR = 2.24; 95%CI: 1.36-3.70, p = 0.002). Consistently, levels of cholesterol (CHOL) (CC+CT vs. TT, 4.44 ± 1.25 vs. 4.10 ± 1.00 mmol/L; p = 0.009) and low density lipoprotein cholesterin (LDL-CH) (CC+CT vs. TT, 2.81 ± 1.07 vs. 2.53 ± 0.82 mmol/L; p = 0.01) in T2DM patients with TT genotype were significant lower than those of CC+CT genotypes. We further validated in MIHA cell that the total cholesterol (TC) level in GRB10-Mut was significantly reduced compared with GRB10-WT; p = 0.0005. Likewise, the reversed palmitic acid (PA) induced lipid droplet formation in GRB10-Mut was more effective than in GRB10-WT. These results suggest that rs1800504 of GRB10 variant may be associated with the blood lipids and then may also related to the risk of CHD in patients with T2DM.

Susceptibility of six polymorphisms in the receptor for advanced glycation end products to type 2 diabetes: a systematic review and meta-analysis

We did a systematic review and meta-analysis, aiming to examine the association of available polymorphisms in the receptor for advanced glycation end products (AGER) gene with the risk of type 2 diabetes. Literature search, eligibility assessment, and data extraction were independently performed by two authors. Risk was expressed as by odds ratio (OR) and 95% confidence interval (CI) under the random-effects model. A total of 26 publications, involving 29 independent studies (8,318 patients with type 2 diabetes and 5,589 healthy or orthoglycemic controls) were included in this meta-analysis. Six polymorphisms in AGER gene, rs2070600, rs1800624, rs1800625, rs184003, rs3134940, and rs55640627, were eligible for inclusion. Overall analyses indicated that the mutations of rs1800624 (-374A) and rs55640627 (2245A) were associated with a significantly increased risk of type 2 diabetes (OR = 1.17 and 1.55, 95% CI: 1.00 to 1.38 and 1.21 to 1.98, respectively). Subsidiary analyses revealed that the mutation of rs2070600 was associated with 2.13-folded increased risk of type 2 diabetes in Caucasians (95% CI: 1.28 to 3.55), and the mutation of rs1800624 was associated with 1.57-folded increased risk in South Asians (95% CI: 1.09 to 2.25), with no evidence of heterogeneity (I²: 42.5% and 44.5%). There were low probabilities of publication bias for all studied polymorphisms. Taken together, our findings indicate an ethnicity-dependent contribution of AGER gene in the pathogenesis of type 2 diabetes, that is, rs2070600 was a susceptibility locus in Caucasians, yet rs1800624 in South Asians.

Association of RAGE rs1800624 and rs1800625 gene polymorphisms with predisposition to optic neuritis and optic neuritis together with multiple sclerosis

Optic neuritis (ON) is demyelinating acute inflammatory disease which affects the optic nerve. ON is classified as a typical (demyelinating) or an atypical (idiopathic). Patients often complain having a periocular pain or a visual loss. The main factor causing the optic neuritis is still unknown. It is believed that it might be a combination of genetic and environmental factors. As the optic neuritis is an inflammation disease, the RAGE gene was selected as it is a part of the inflammation process.

AIM

to determine the relation between RAGE rs1800624 and rs1800625 genotypes of patients who have a manifestation of optic neuritis and optic neuritis with multiple sclerosis together in Lithuanian population and visual acuity recovery.

OBJECTIVES

patients with optic neuritis and healthy controls individuals were examined. Genotyping was carried out by using the instrument of real-time polymerase chain reaction called StepOnePlus (AppliedBiosystems). Statistical analysis was performed using IBM SPSS Statistics 20.0 software and free PLINK software (version 1.07).

RESULTS

Results indicate that rs1800624 polymorphism is not statistically significant in optic neuritis manifestation (p = .392), while rs1800625 GG genotype is associated with 7.5-fold increased odds of ON development under the codominant model (OR = 7.5; 95% CI:1.796-31.313; p = .006) and with 6.9-fold increased odds under the recessive model OR = 6.862; 95% CI:1.665-28.288; p = .008); and each allele G is associated with 1.9-fold increased odds of ON development under the additive model (OR = 1.879; 95% CI:1.149-3.072; p = .012). The haplotype containing A-G alleles in rs1800624 and rs1800625 was statistically significantly associated with increased risk for ON development (χ2 = 13.23; p < .001). Both polymorphisms do not have statistically significant importance in relation to visual acuity recovery.

CONCLUSIONS

RAGE rs1800625 AA genotype decreases the risk of optic neuritis. The single nucleotide polymorphisms RAGE rs1800624 and rs1800625 do not have a statistically significant importance in relation with visual acuity recovery.

Polymorphisms of the receptor for advanced glycation end products as vasculopathy predictor in sickle cell disease

BACKGROUND

The genetic variants of the receptor for advanced glycation end products (RAGE) gene have been associated with vascular disease risk. The objective of this work was to explore the association of three single-nucleotide polymorphisms (SNPs) of RAGE gene (374T/A, 429T/C, and G82S) with vascular complications in SCD.

METHODS

The study was conducted on 40 children with SCD and 40 healthy children served as controls. All participants were genotyped for the three studied RAGE polymorphisms by polymerase chain reaction (PCR).

RESULTS

Regarding 374T/A polymorphism, the frequency of TA, TT genotypes and T allele were higher in patients (p < 0.001). T allele was associated with higher incidence of sickling crisis and stroke (p < 0.05). In the subgroup analyses of 429T/C polymorphism, an association between C allele and SCD vascular complications was observed (p < 0.05). Concerning the frequency of G82S genotypes of RAGE, GG variant was detected in 39 (97.5%) of the patients, as compared with 40 (100%) of controls (p = 0.3). A regression analysis proved that HbS%, serum ferritin, and the -374T and 429C alleles were significant independent predictors of frequent sickling episodes (p < 0.05).

CONCLUSIONS

The C allele of -429T/C and T allele of 374T/A RAGE polymorphisms may be considered as predictors for vascular dysfunction in SCD.

IMPACT

The C allele of -429T/C and T allele of 374T/A RAGE polymorphisms may be considered as predictors for vascular dysfunction in SCD patients. To our knowledge, our study is the first exploring the association of three single-nucleotide polymorphisms of RAGE gene (374T/A, 429T/C, and G82S) with vascular complications in SCD. Early identification of patients carrying these genetic variants might be of great importance not only to identify subjects at risk of vasculopathy but also to direct them to RAGE-targeted treatments.

Reduced endogenous secretory RAGE in blood and bronchoalveolar lavage fluid is associated with poor prognosis in idiopathic pulmonary fibrosis

Background

The endogenous secretory receptor for advanced glycation end products (esRAGE) is a soluble isoform produced by alternative splicing of the RAGE gene. The isoform has anti-inflammatory properties due to its inhibition of the RAGE/ligand interaction and is reduced in the lung tissue of patients with idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the association of esRAGE serum and bronchoalveolar lavage fluid (BALF) levels with progression of IPF.

Methods

This study included 79 IPF patients and 90 healthy controls. IPF and control serum esRAGE levels were compared, and the correlation between serum and BALF esRAGE levels was analyzed in 57 IPF patient samples. We also investigated the relationship of esRAGE serum and BALF levels with prognoses and lung function parameters in patients with IPF.

Results

Serum esRAGE levels in IPF patients were significantly lower than those in healthy controls (162.0 ± 102.4 ng/ml and 200.7 ± 107.3 ng/ml, p = 0.009), although the baseline characteristics of age and smoking history were not matched. Serum levels of esRAGE were correlated with BALF esRAGE levels (r_s = 0.317). The BALF esRAGE levels were also correlated with diffusion capacity for carbon monoxide (r_s = 0.406). A Kaplan-Meier curve analysis and univariate/multivariate Cox hazard proportion analysis revealed that lower levels of esRAGE in blood and BALF were significantly associated with poorer prognoses in patients with IPF.

Conclusions

Decreased esRAGE levels in BALF and blood were associated with poor prognoses in patients with IPF. These results suggest that esRAGE could be related to the pathophysiology of IPF and serum esRAGE could be a potential prognostic marker of IPF.

Pathological Implications of Receptor for Advanced Glycation End-Product (AGER) Gene Polymorphism

The receptor for advanced glycation end-products (RAGE) is a cell surface transmembrane multiligand receptor, encoded by the AGER gene. RAGE presents many transcripts, is expressed mainly in the lung, and involves multiple pathways (such as NFκB, Akt, p38, and MAP kinases) that initiate and perpetuate an unfavorable proinflammatory state. Due to these numerous functional activities, RAGE is implicated in multiple diseases. AGER is a highly polymorphic gene, with polymorphisms or SNP (single-nucleotide polymorphism) that could be responsible or co-responsible for disease development. This review was designed to shed light on the pathological implications of AGER polymorphisms. Five polymorphisms are described: rs2070600, rs1800624, rs1800625, rs184003, and a 63 bp deletion. The rs2070600 SNP may be associated with the development of human autoimmune disease, diabetes complications, cancer, and lung diseases such as chronic obstructive pulmonary disease and acute respiratory distress syndrome. The rs1800624 SNP involves AGER gene regulation and may be related to reduced risk of heart disease, cancer, Crohn's disease, and type 1 diabetes complications. The rs1800625 SNP may be associated with the development of diabetic retinopathy, cancer, and lupus but may be protective against cardiovascular risk. The rs184003 SNP seems related to coronary artery disease, breast cancer, and diabetes. The 63 bp deletion may be associated with reduced survival from heart diseases during diabetic nephropathy. Here, these potential associations between AGER polymorphisms and the development of diseases are discussed, as there have been conflicting findings on the pathological impact of AGER SNPs in the literature. These contradictory results might be explained by distinct AGER SNP frequencies depending on ethnicity.

Promoter methylation cooperates with SNPs to modulate RAGE transcription and alter UC risk

Single-nucleotide polymorphisms (SNPs) located in the promoter region of the receptor for advanced glycation end products (RAGE) gene have been linked to the activity of RAGE. However, contrary to our expectation, we previously detected no correlation between SNPs within the RAGE promoter and ulcerative colitis (UC) risk in a case-control study. Here, we investigated the methylation of the RAGE promoter and analyzed the collective contribution of methylation and SNPs to UC risk. We found that RAGE promoter hypomethylation was more common in UC patients compared to controls (70% vs. 30%, respectively), as determined via bisulfite sequencing PCR (BSP) and methylation-specific PCR (MSP). Furthermore, we investigated the cooperativity of promoter methylation and SNPs and found that either of two SNPs (rs1800624 or rs1800625) and promoter methylation jointly contributed to UC risk (30 UC patients vs. 30 controls, P < 0.05). There was no correlation between UC risk and either methylation or SNPs when analyzed separately. This lack of correlation is likely due to promoter methylation repressing gene transcription, whereas SNPs in the RAGE promoter region activate RAGE transcription. We found that variant allele carriers with promoter hypomethylation were at an increased risk for UC (rs1800624, OR = 10, 95% CI: 1.641-60.21, P = 0.009; rs1800625, OR = 4.8, 95% CI: 1.074-21.447, P = 0.039). Furthermore, our data revealed that the RAGE mRNA levels in variant allele carriers with promoter hypomethylation were significantly higher compared to those with promoter hypermethylation (P < 0.05) as well as to those in wild-type allele individuals exhibiting promoter hypomethylation (P < 0.05). We therefore speculate that the methylation status and SNPs present in the RAGE promoter region alter RAGE transcription, thereby impacting UC risk. We also propose that the methylation status and RAGE promoter genotype could jointly serve as clinical biomarkers to assist in UC risk assessment.

The Oxidative Stress and Mitochondrial Dysfunction during the Pathogenesis of Diabetic Retinopathy

Diabetic retinopathy is one of the most serious microvascular complications induced by hyperglycemia via five major pathways, including polyol, hexosamine, protein kinase C, and angiotensin II pathways and the accumulation of advanced glycation end products. The hyperglycemia-induced overproduction of reactive oxygen species (ROS) induces local inflammation, mitochondrial dysfunction, microvascular dysfunction, and cell apoptosis. The accumulation of ROS, local inflammation, and cell death are tightly linked and considerably affect all phases of diabetic retinopathy pathogenesis. Furthermore, microvascular dysfunction induces ischemia and local inflammation, leading to neovascularization, macular edema, and neurodysfunction, ultimately leading to long-term blindness. Therefore, it is crucial to understand and elucidate the detailed mechanisms underlying the development of diabetic retinopathy. In this review, we summarized the existing knowledge about the pathogenesis and current strategies for the treatment of diabetic retinopathy, and we believe this systematization will help and support further research in this area.

Polymorphisms in the receptor for advanced glycation end-products (RAGE) gene and circulating RAGE levels as a susceptibility factor for non-alcoholic steatohepatitis (NASH)

Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome and major cause of chronic liver disease in developed countries. Its prevalence is increasing in parallel with the prevalence of obesity and other components of the metabolic syndrome. As the liver is central to the clearance and catabolism of circulating advanced glycosylation end-products (AGEs), AGEs and their cognate receptors—RAGE (receptor for AGEs) system might be involved in NAFLD in obese patients. To examine this, we investigated four common polymorphisms of RAGE gene: 1704G/T (rs184003), G82S (rs2070600), -374T/A (rs1800624) and −429T/C (rs1800625) in 340 obese patients with metabolic syndrome. and protein levels of AGE and RAGE. This is the first study to describe association of 4 common polymorphisms with non-alcoholic steatohepatitis (NASH) as well as to examine protein levels of RAGE and AGE. Univariate analysis showed patients carrying the rs1800624 heterozygote genotype (AT) exhibited 2.36-fold increased risk of NASH (odds ratio (OR) = 2.36; 95% confidence interval (95% CI): 1.35–4.19) after adjusting for confounders. The minor allele -374 A has been shown to suppress the expression of RAGE protein. The protein levels of esRAGE, total sRAGE and AGE protein levels did not correlate with each other in obese patients with no liver disease, indicative of RAGE signaling playing an independent role in liver injury. In obese patients with non-NASH NAFLD and NASH respectively, esRAGE protein showed strong positive correlation with total sRAGE protein. Further, haplotype analysis of the 4 SNPs, indicated that haplotype G-A-T-G was significantly associated with 2-fold increased risk for NASH (OR = 2.08; 95% CI: 1.21–3.5; P = 0.006) after adjusting for confounders. In conclusion, the presented data indicate that the G-A-T-G haplotype containing minor allele at position −374 A and major allele at position −429T, 1704G, and G82S G could be regarded as a marker for NASH.

Association between the RAGE (receptor for advanced glycation end-products) -374T/A gene polymorphism and diabetic retinopathy in T2DM

OBJECTIVE

Interaction between advanced glycation end-products (AGEs) and receptor for AGEs (RAGE) in cells could affect both extracellular and intracellular structure and function, which plays a pivotal role in diabetic microvascular complications. The results from previous epidemiological studies on the association between RAGE gene -374T/A polymorphism and diabetic retinopathy (DR) risk were inconsistent. Thus, we conducted this meta-analysis to summarize the possible association between RAGE -374T/A polymorphism and DR risk.

METHOD

We searched all relevant articles on the association between RAGE -374T/A polymorphism and DR risk from PubMed, Cochrane Library, ScienceDirect, Wanfang, VIP and Chinese National Knowledge Infrastructure (CNKI) web databases up to August 2016. Odds ratio (OR) with 95% confidence interval (CI) were calculated to assess those associations. All analyses were performed using the Review Manager software.

RESULTS

Nine case-control studies, including 1,705 DR cases and 2,236 controls were enrolled, and the results showed that the A allele of RAGE -374T/A polymorphism was significantly associated with increased DR risk in dominant model (TA/AA vs. TT: OR=1.22, 95CI 1.05-1.41, p=0.006) and heterozygote model (TA vs. TT: OR=1.26, 95CI 1.07-1.47, p=0.005). The subgroup analysis by ethnicity showed that significantly increased DR risk was found in both Asian and Caucasian populations.

CONCLUSION

This meta-analysis reveals that the A allele of RAGE -374T/A polymorphism probably increase DR risk.

Polymorphism related to cardiovascular risk in hemodialysis subjects: a systematic review

Cardiovascular disease (CVD) is one of the leading causes of mortality in hemodialysis (HD) subjects. In addition to the traditional risk factors that are common in these individuals, genetic factors are also involved, with emphasis on single nucleotide polymorphs (SNPs). In this context, the present study aims to systematically review the studies that investigated the polymorphisms associated with cardiovascular risk in this population. In general, the SNPs present in HD individuals are those of genes related to inflammation, oxidative stress and vascular calcification, also able of interfering in the cardiovascular risk of this population. In addition, polymorphisms in genes related to recognized risk factors for CVD, such as dyslipidemia, arterial hypertension and left ventricular hypertrophy, also influence cardiovascular morbidity and mortality.

Diagnostic indicator of acute lung injury for pediatric critically ill patients at a tertiary pediatric hospital

Early identification of acute lung injury (ALI) in pediatric patients at risk of mortality is important for improving outcome.Assessment of soluble form of receptor for advanced glycation end products (sRAGE) as a valid biomarker for diagnosis of ALI among critically ill, pediatric patients in addition to correlating levels of sRAGE and different outcomes of those patients.A Hospital-based case-control study was conducted in pediatric intensive care units (PICUs) at Cairo University Hospital, along a period of 6 months. Total of 68 pediatric patients following inclusion criteria were classified into: patients with ALI; with both ALI and sepsis; with sepsis and control patients. They were prospectively followed and their laboratory and immunological workup (at days 1 and 9) was done to measure serum sRAGE levels and detect (sRAGE) genotypes.The age of the included children ranged from 8 to 84 months. Plasma level of sRAGE was significantly higher in plasma from patients with ALI regardless of associated sepsis. Plasma sRAGE levels were positively correlated with lung injury score. When assessing sRAGE genotypes, TA and TT genotypes were significant in most of the ALI with and without sepsis patients.Monitoring levels of sRAGE and genotypes can significantly affect the survival of ALI children.

Receptor for advanced glycation end-products and ARDS prediction: a multicentre observational study

Acute respiratory distress syndrome (ARDS) prediction remains challenging despite available clinical scores. To assess soluble receptor for advanced glycation end-products (sRAGE), a marker of lung epithelial injury, as a predictor of ARDS in a high-risk population, adult patients with at least one ARDS risk factor upon admission to participating intensive care units (ICUs) were enrolled in a multicentre, prospective study between June 2014 and January 2015. Plasma sRAGE and endogenous secretory RAGE (esRAGE) were measured at baseline (ICU admission) and 24 hours later (day one). Four AGER candidate single nucleotide polymorphisms (SNPs) were also assayed because of previous reports of functionality (rs1800625, rs1800624, rs3134940, and rs2070600). The primary outcome was ARDS development within seven days. Of 500 patients enrolled, 464 patients were analysed, and 59 developed ARDS by day seven. Higher baseline and day one plasma sRAGE, but not esRAGE, were independently associated with increased ARDS risk. AGER SNP rs2070600 (Ser/Ser) was associated with increased ARDS risk and higher plasma sRAGE in this cohort, although confirmatory studies are needed to assess the role of AGER SNPs in ARDS prediction. These findings suggest that among at-risk ICU patients, higher plasma sRAGE may identify those who are more likely to develop ARDS.

Association of RAGE gene polymorphism with Type-2 diabetes mellitus in local population

Objectives:

Type-2 diabetes mellitus (T2DM) is an endocrine disease having a significant genetic component. Polymorphisms of many genes may affect hereditary vulnerability of the disease that is characterized by insulin resistance and islet disorder. As the genetic basis of T2DM can vary between ethnic groups, it is important to investigate the genetic link of T2DM in Pakistani populace. This study was aimed to assess the association of receptor for advanced glycation end product (RAGE) gene polymorphism (-429T>C) with Type-2 diabetes mellitus within local populace.

Methods:

Genomic DNA was isolated by following kit protocol. Genotyping of the RAGE gene was studied by PCR-RFLP on genomic DNA. All research work was done in molecular biochemistry laboratory (MBL), University of Agriculture Faisalabad and Postgraduate Laboratory, The University of Faisalabad, Pakistan from December 2016 to July 2017.

Results:

We found distribution of -429T>C genotypes between T2DM and healthy controls as 24.7% (tt), 24.7% (Tt) and 50.7% (TT). The outcomes were highly compatible statistically.

Conclusion:

The techniques of PCR and RFLP when performed simultaneously can be helpful in tracing vital information regarding polymorphism of AGE receptor.

Genetic predisposition to ischaemic stroke by RAGE and HMGB1 gene variants in Chinese Han population

Emerging evidence suggests that the multiligand receptor for advanced glycation end products (RAGE) and its ligand high mobility group box 1 protein (HMGB1) contribute to the pathophysiology of ischaemic stroke (IS). The present study aimed to investigate the association of RAGE and HMGB1 variants with the risk of IS. A total of 1,034 patients and 1,015 age- and sex-matched healthy controls were genotyped to detect five genetic variants of the RAGE gene and four genetic variants of the HMGB1 gene using the Multiplex SNaPshot assay. We found that the rs2070600 variant of RAGE was associated with an increased risk of IS (OR = 1.19, 95% CI: 1.02-1.38, P = 0.043), whereas the rs2249825 variant of HMGB1 was associated with a decreased risk of IS (OR = 0.83, 95% CI: 0.71-0.98, P = 0.041). Further stratification by IS subtypes revealed that the presence of the TT genotype of the RAGE rs2070600 variant confers a higher risk of the large artery atherosclerosis subtype of IS (P = 0.036). Moreover, patients with the variant T allele of the RAGE rs2070600 variant presented with reduced serum soluble RAGE production. Patients carrying the variant G allele of the HMGB1 rs2249825 variant exhibited significantly lower infarct volumes than those with the major CC genotype. These clues may help in the development of optimal personalized therapeutic approaches for IS patients.

AGER rs2070600 polymorphism elevates neutrophil-lymphocyte ratio and mortality in metastatic lung adenocarcinoma

Background

The receptor for advanced glycation end-product (RAGE) is a multi-ligand receptor involved in inflammation. In the gene encoding RAGE (AGER), there are three well-known polymorphisms; rs2070600, rs1800624, and rs1800625, which potentially increase the risk of lung cancer. Remarkably, AGER rs2070600 polymorphism, which increases ligand-binding affinity, is a potential prognostic factor in non-small cell lung cancer, but the underlying mechanism is unclear. The neutrophil-lymphocyte ratio (NLR) reflects tumor-associated systemic inflammatory conditions; high ratios are associated with poor prognosis in multiple cancers. Additionally, some humoral factors via RAGE-signaling are associated with elevated NLR in cancer patients.

Objectives

Associations of AGER polymorphisms with disease susceptibility, prognosis, and NLR were investigated in Japanese patients with lung adenocarcinoma.

Methods

We included 189 patients with lung adenocarcinoma, 96 of which had distant metastases, and 303 healthy controls. The correlation between AGER polymorphisms (rs2070600, rs1800624, rs1800625) and disease susceptibility and factors elevating the mortality and NLR in patients with metastases were evaluated.

Results

Only the minor allele of rs2070600 was associated with a higher NLR (β = 0.209, p = 0.043) and a poor prognosis (Hazard ratio = 2.06, 95% Confidence interval = 1.09-3.77, p = 0.028) in patients with metastatic disease, independently of background characteristics, including EGFR mutation status. All three polymorphisms were not associated with the risk of lung adenocarcinoma.

Conclusions

The AGER rs2070600 polymorphism was independently associated with systemic inflammation and poor prognosis in patients with metastatic lung adenocarcinoma.

NADPH oxidase p22phox C242T polymorphism is associated with macroalbuminuria in diabetic patients: A meta-analysis

AIMS

Previous studies suggested an association between C242T polymorphism in NADPH Oxidase p22phox and diabetic nephropathy (DN) risk, but the results were inconsistent. To obtain a more precise estimation, we carried out a meta-analysis to analyze the effect of C242T polymorphism in NADPH Oxidase p22phox on DN risk.

METHODS

We searched PubMed, ISI Web of Science, and China National Knowledge Infrastructure for all eligible case-control studies through May 2016. The odds ratios (ORs), together with the 95% confidence intervals (CIs), were calculated to evaluate the strength of association between C242T SNP in NADPH Oxidase p22phox on DN risk.

RESULTS

Overall, ten eligible studies involving a total of 1894 cases and 1746 controls were included in our meta-analysis. The results showed that there was no statistical evidence of association between NADPH oxidase p22phox C242T polymorphism and DN in all genetic models (T vs. C: OR 1.16, 95% CI 0.85-1.59, p=0.34; TT vs. CC: OR 1.49, 95% CI 0.80-2.76, p=0.21; TT/CT vs. CC: OR 1.18, 95% CI 0.81-1.72, p=0.40; TT vs.

CT/CC

OR 1.31, 95% CI 0.82-2.11, p=0.26). However, significant association was found in diabetic patients with macroalbuminuria.

CONCLUSION

This meta-analysis indicates that NADPH oxidase p22phox C242T polymorphism is associated with macroalbuminuria in diabetic patients. However, this conclusion should be interpreted with caution due to the small sample size. Larger sample-size studies with homogeneous patients and well-matched controls are required.

Association of single-nucleotide polymorphisms in the RAGE gene and its gene- environment interactions with diabetic nephropathy in Chinese patients with type 2 diabetes

Aims

To investigate the association of several single nucleotide polymorphisms (SNPs) within RAGE gene and additional gene- smoking interaction with diabetic nephropathy (DN) risk in Chinese patients with type 2 diabetes mellitus (T2DM).

Methods

A total of 865 participants (570 males, 295 females) were selected, including 430 T2DM complicated DN patients and 435 controls (T2DM patients without DN). Generalized multifactor dimensionality reduction (GMDR) was used to screen the best interaction combination among SNPs and smoking. Logistic regression was performed to investigate impact of 4 SNPs within RAGE gene, additional gene- smoking interaction on DN risk.

Results

DN risk was significantly higher in carriers with the C allele of rs1800625 than those with TT genotype, adjusted OR (95%CI) =1.57 (1.16-2.17), and higher in carriers with the T allele of rs184003 than those with GG genotype, adjusted OR (95%CI) = 1.64 (1.21-2.12). GMDR model indicated a significant two-locus model (p=0.0010) involving rs1800625 and smoking, the cross-validation consistency of this two- locus model was 10/ 10, and the testing accuracy was 60.72%. We also conducted stratified analysis for the significant models in the GMDR analysis by using logistic regression. We found that current smokers with rs1800625- TC or CC genotype have the highest DN risk, compared with never- smokers with rs1800625- TT genotype, OR (95%CI) = 2.92 (1.94 -3.96), after covariates adjustment.

Conclusions

We found that the C allele of rs1800625 and the T allele of rs184003 within RAGE gene, interaction between rs1800625 and smoking were all associated with increased DN risk.

RAGE polymorphisms and oxidative stress levels in Hashimoto's thyroiditis

BACKGROUND

Polymorphisms of the receptor for advanced glycation end products (RAGE) gene have been studied in various autoimmune disorders, but not in Hashimoto's thyroiditis. Also, increased oxidative stress has been described in patients with Hashimoto's thyroiditis. The aim of this study was to investigate the possible role of two common RAGE polymorphisms (-429T>C, -374T>A) in Hashimoto's thyroiditis; in parallel, we studied oxidative stress levels.

MATERIALS AND METHODS

A total of 300 consecutive euthyroid women were examined and classified into three groups: Hashimoto's thyroiditis with treatment (n = 96), Hashimoto's thyroiditis without treatment (n = 109) and controls (n = 95). For a rough evaluation of oxidative stress, total lipid peroxide levels in serum were measured. The -429T>C AluI and -374T>A MfeI polymorphisms of RAGE were studied in genomic DNA.

RESULTS

Significant association of the RAGE system with Hashimoto's thyroiditis was found only with regard to the prevalence of the -429T>C, but not with -374T>A polymorphism. The levels of oxidative stress were significantly elevated in Hashimoto's thyroiditis patients under treatment. Further analysis demonstrated that an oxidative stress cut-off value of 590 μmol/L is associated with an increased risk of progression of Hashimoto's thyroiditis from euthyroidism to hypothyroidism; this risk is further increased in carriers of the RAGE -429T>C polymorphism.

CONCLUSIONS

Our findings indicate that both examined risk factors may be implicated in the occurrence of Hashimoto's thyroiditis, but this covers only a fraction of the pathophysiology of the disease.

Predictive Nomogram of RAGE Genetic Polymorphisms and Metabolic Risk Factors for Myocardial Infarction Risk in a Han Chinese Population

We investigated the association of 4 well-characterized polymorphisms in receptor for the advanced glycation end-product ( RAGE) gene with myocardial infarction (MI) risk and the changes in metabolic risk factors among 717/612 patients/controls, with the aim of constructing a predictive nomogram. The genotype/allele distributions differed significantly between the 2 groups for T-429C ( Pgenotype/allele = .004/.001) and G1704T ( P < .001/.001). T-429C was significantly associated with MI risk, especially under a recessive model (adjusted odds ratio: 2.24, 95% confidence interval: 1.33-3.79, P = .003). For G1704T, significance was detected under additive (1.37; 1.12-1.67; P = .002) and recessive (3.86; 2.27-6.57; P < .001) models. There were significant differences in blood pressure and low-density lipoprotein cholesterol (LDL-C) across T-429C genotypes and in total cholesterol and LDL-C across G1704T genotypes. The overall best multifactor dimensionality reduction model included dyslipidemia, G1704T, and T-429C. Further predictive nomogram on 2 significant polymorphisms, blood pressure and lipids, showed a better predictive capability (concordance index = 0.716, P < .001). Altogether, we identified 2 polymorphisms of RAGE, T-429C and G1704T, which interacted with metabolic risk factors associated with the occurrence of MI. We also constructed a genetic–metabolic nomogram that can better predict MI risk.

Association of Polymorphisms of the Receptor for Advanced Glycation Endproducts Gene with Schizophrenia in a Han Chinese Population

Receptor for Advanced Glycation Endproducts (RAGE) is a member of the immunoglobulin superfamily that binds diverse ligands involved in the development of inflammatory damage and diverse chronic diseases including schizophrenia. Here, three single-nucleotide polymorphisms (SNPs) (G82S, -374T/A, and -429T/C) in the RAGE gene were genotyped in 923 patients with schizophrenia and 874 healthy-matched controls in a Han Chinese population using the SNaPshot technique. Additionally, we investigated the association among aforementioned SNPs with the clinical psychotic symptoms of the patients and neurocognitive function. Our study demonstrated that the frequencies of the TC + CC genotypes and the C allele in the -429T/C polymorphism were significantly lower in the patients compared with the controls (p = 0.031 and p = 0.034, resp.). However, the significant effect disappeared when using Bonferroni correction (p = 0.093 and p = 0.102, resp.). And there were no significant differences in the genotype and allele frequencies between the patients and the controls for G82S and -374T/A polymorphisms. Additionally, the -429T/C C allele carriers had marginally higher Symbol coding scores than the subjects with the TT genotypes [p = 0.031 and p (corr) = 0.093]. Our data indicate that the RAGE -429T/C polymorphism may be associated with the susceptibility of schizophrenia.

Methylglyoxal-Derived Advanced Glycation Endproducts in Multiple Sclerosis

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

Candidate gene studies of diabetic retinopathy in human

Diabetic retinopathy (DR) is a multifactorial disease with complex pathophysiology. It is the main cause of blindness among the people in productive age. The purpose of this literature review is to highlight recent achievements in the genetics of diabetic retinopathy with particular focus on candidate gene studies. We summarized most of the available published data about candidate genes for diabetic retinopathy with the goal to identify main genetic aspects. We conclude that genetic studies reported contradictory findings and no genetic variants meet criteria of a diagnostic marker, or significantly elucidate the root of DR development. Based on these findings it is important to continue with the research in the field of DR genetics, mainly due to the fact that currently new possibilities and approaches associated with utilization of next-generation sequencing are available.

Association of genetic variants in the receptor for advanced glycation end products gene with diabetic retinopathy: A meta-analysis

BACKGROUND

Diabetic retinopathy (DR) is a major sight-threatening diabetic complication. Previous studies have examined the association of DR with multiple genetic variants in the receptor for advanced glycation end products (RAGE) gene, with inconsistent results.

OBJECTIVE

To perform a systematic literature search and conduct meta-analyses to examine the association of genetic variants in RAGE with DR.

DATA SOURCES

PubMed, Cochrane Library, Embase, Google Scholar, and HuGE.

STUDY ELIGIBILITY CRITERIA AND PARTICIPANTS

Studies were on human subjects; the studies were case-control ones and included subjects who had DR and those who did not have DR; and the studies provided genotype data for genetic variants in RAGE, separately for subjects who had and did not have DR, or provided odds ratios (ORs) and the 95% confidence intervals (CIs), or provided sufficient data for the calculation of OR and the 95% CI.

STUDY APPRAISAL AND SYNTHESIS METHODS

We used OR as a measure of association, and used random-effects model in all the meta-analyses. Between-study heterogeneity was assessed using I, and publication bias was evaluated using Egger test.

RESULTS

A total of 13 studies met the eligibility criteria and were included in our analyses. We found that Gly82Ser was significantly associated with DR (OR = 2.40, 95% CI: 1.46-3.97; P = 0.001) using a recessive model. -374T/A also showed significant association with DR under a dominant model (OR = 1.21, 95% CI: 1.03-1.43; P = 0.023). We did not find a significant association of DR with other genetic variants in RAGE.

LIMITATIONS

The number of included studies is small for some genetic variants; duration of diabetes varied across studies; most studies were conducted in Asia; and it is not clear whether the observed association can be generalized to other ethnicities; and we could not control for other potential confounding factors.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

We found that Gly82Ser in RAGE showed significant association with DR. More studies with larger sample sizes that control for important risk factors, such as duration of diabetes, are needed to validate our findings.

Association of vascular endothelial growth factor -634G/C and receptor for advanced glycation end products G82S gene polymorphisms with diabetic retinopathy

AIM

To investigate the association of receptor for advanced glycation end products (RAGE) G82S and vascular endothelial growth factor (VEGF) -634 G/C gene polymorphisms with diabetic retinopathy (DR).

METHODS

Our cross-sectional study included 61 diabetic patients, 12 of them had proliferative diabetic retinopathy (PDR), 15 had non proliferative diabetic retinopathy (NPDR), 34 had no diabetic retinopathy (NDR) and 61 healthy controls. Participants were tested for RAGE G82S and VEGF -634 G/C polymorphisms by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

We found a significant association between VEGF -634 G/C polymorphism and PDR as PDR patients had increased incidence of VEGF -634 CC genotype compared to NDR patients [odds ratio for CC vs (GC+GG)=6.5, 95% CI=1.5-27.8, P=0.021]. Also VEGF -634 CC genotype and C allele were significantly higher in the PDR than in NPDR patients, which is a novel finding in our study (P=0.024, 0.009 respectively). The mean triglycerides level was significantly higher in diabetic patients with CC genotype (P=0.01) as compared to patients with other genotypes. All cases and control subjects were of the same heterozygous RAGE 82G/S genotype.

CONCLUSION

Patients carrying VEGF -634 C polymorphism have a higher risk of PDR development, so VEGF -634 G/C polymorphism could be used as a predictive marker for PDR in diabetic patients. We could not find a significant association between RAGE G82S polymorphism and DR.

The promoter polymorphisms of receptor for advanced glycation end products were associated with the susceptibility and progression of sepsis

Receptor for advanced glycation end products (RAGE) is considered a major pattern recognition receptor, which plays an important role in the development of sepsis. Increasing evidence showed an association between RAGE polymorphisms and the susceptibility to several inflammatory-related diseases. However, little is known about the clinical relationship between RAGE polymorphisms and sepsis. In this study, we analyzed the association of sepsis with three functional RAGE gene polymorphisms (rs1800624, rs1800625 and rs2070600) in a Chinese Han population (372 sepsis cases and 400 healthy controls). Significant differences were observed in the rs1800624 and rs1800625 genotype/allele distributions between the sepsis and controls, but no significant difference was observed in the rs2070600 genotype/allele. Moreover, our results also revealed a significant difference in the genotype/allele frequencies of the rs1800624 and rs1800625 polymorphisms between the sepsis and severe sepsis subtypes, the rs1800624 TT or rs1800625 TT genotype carriers exhibited a significant increase in RAGE mRNA, sRAGE, TNF-α and IL-6 expression compared with the rs1800624 AT/AA or rs1800625 CT/CC carriers in sepsis patients. Overall, this study might provide valuable clinical evidence between the RAGE gene polymorphisms and the risk or the development of sepsis.

The-374T/A Variant of the Rage Gene Promoter is Associated with Clinical Restenosis after Coronary Stent Placement

Upregulation of the receptor for advanced glycation end products (RAGE) may play a crucial role in neointimal formation upon vessel injury. The −374T/A variant of the RAGE gene promoter, which has been associated with an altered expression of the cell-surface receptor, could exert a protective effect toward the development of vascular disease. The aim of this study is to determine the impact of this common genetic variant in the occurrence of clinical in-stent restenosis after coronary stent implantation. The −374T/A polymorphism of the RAGE gene promoter was evaluated by PCR-RFLPs in 267 patients with coronary artery disease who underwent coronary stent implantation and a subsequent coronary angiography 6–9 months later for suspected restenosis. In-stent restenosis was assessed by means of quantitative angiography. Carriers of the-374AA genotype showed a significantly reduced risk of developing restenosis after percutaneous transluminal intervention than non-carriers. To determine whether the protective effect of the homozygous AA genotype toward clinical restenosis was independent of potential confounders, we performed multivariable logistic regression analysis. After allowance for clinical and biochemical risk factors and stent length, the AA genotype remained significantly associated with a reduced prevalence of in-stent restenosis. No relation was evident between the RAGE genotype and established cardiovascular risk factors. In conclusion, the −374AA genotype of the RAGE gene promoter could be associated with a reduced risk of in-stent restenosis after coronary stent implantation.

RAGE and CYBA polymorphisms are associated with microalbuminuria and end-stage renal disease onset in a cohort of type 1 diabetes mellitus patients over a 20-year follow-up

AIMS

We investigated the association of polymorphisms of three genes implicated in oxidative stress: CYBA C242T, RAGE -374T/A and -429T/C, and ALOX12 Arg261Gln, with the delay of microalbuminuria onset in patients with type 1 diabetes mellitus (DT1).

METHODS

A total of 162 T1D patients presenting with diabetes for 32.9 ± 9 years were included in the study; 53 had persistent microalbuminuria (>30 mg/l) and 109 did not. Onset of diabetes, microalbuminuria and end-stage renal disease (ESRD) were recorded as bio-clinical data. We determined polymorphism association of microalbuminuria with a Cox regression model.

RESULTS

All polymorphisms respected the Hardy-Weinberg equilibrium. The Cox regression model validated four significant variables associated with microalbuminuria: RAGE 374AA (HR 4.19 [1.84-9.58] (p = 0.001)), CYBA TT+TC (HR 2.1 [1.16-3.80], p = 0.015), male sex (HR 1.92 [1.07-3.43], p = 0.028) and diabetes diagnosis at the pediatric stage (HR 1.85 [1.03-3.32], p = 0.039). The same association was found with ESRD (p = 0.028 and p = 0.033 for CYBA TC+TT and RAGE 374AA, respectively). CYBA C242T and RAGE 374T/A were not significantly associated with diabetic retinopathy.

CONCLUSIONS

CYBA C242T and RAGE -374T/A correlate with microalbuminuria onset in the French DT1 cohort. The same correlation with ESRD onset supports the argument for the involvement of a genetic predisposition involving kidney-specific oxidative stress for diabetic nephropathy.