Association of the Gly82Ser polymorphism in the receptor for advanced glycation end products (RAGE) gene with circulating levels of soluble RAGE and inflammatory markers in nondiabetic and nonobese Koreans

RAGE genetic polymorphisms are associated with risk, chemotherapy response and prognosis in patients with advanced NSCLC

AIM

To explore the association between genetic polymorphisms of the receptor for advanced glycation end-products (RAGE) and susceptibility, chemotherapy response rate and prognosis of non-small cell lung cancer (NSCLC).

METHOD

This is a prospective study in which 562 patients with NSCLC and 764 healthy controls were enrolled. Three RAGE genetic polymorphisms, namely, -429T/C, -374T/A and 82G/S were genotyped. Platinum-based chemotherapy was given to 432 subjects with advanced inoperable NSCLC and their responses to chemotherapy were evaluated.

RESULTS

All the polymorphic genotypes of RAGE polymorphisms were associated with susceptibility for NSCLC. Only the 82G/S polymorphisms denoted a significant difference between responders and non-responders to chemotherapy. The 82SS genotype and 82S allele distribution not only increased the NSCLC risk, but also was associated with a lower chemotherapy response rate and poor prognosis, indicated by overall survival and progression free survival.

CONCLUSION

The 82G/S genetic polymorphism of RAGE gene might be used as a genetic marker to screen for patients sensitive to thermotherapy and to predict the prognosis of NSCLC.

The interaction between obesity and RAGE polymorphisms on the risk of knee osteoarthritis in Chinese population

BACKGROUND

The receptor for advanced glycation end products (RAGE) has been reported to relate to osteoarthritis (OA), however, the role of RAGE genetic variants in OA remains unknown.

METHOD

A total of 233 patients with primary knee OA and 255 healthy volunteer were recruited. Three RAGE gene polymorphisms, namely, Gly82Ser (rs2070600). -374T/A (rs1800624) and 429T/C (rs1800625) were genotyped.

RESULTS

Of all three RAGE gene polymorphisms, only the genotype distributions and alleles frequencies of 82G/S polymorphisms significantly differed between knee OA and control subjects. The presence of SS genotype and S allele of 82G/S we significantly higher in knee OA subjects than in controls (34.76% vs. 19.61%, P for trend =0.004; 57.64% vs. 48.59%, P for trend <0.001, respectively). Multivariate logistic regression analysis showed a significantly increased risk for knee OA for the SS genotype compared with the AA genotype (OR= 1.984, 95% CI: 1.238-3.181; P =0.004). The adjusted OR for S allele carriage was significantly higher than G allele carriage (OR=1.440, 95% CI: 1.137-1.8231, P=0.002). Moreover, a significant multiplicative interaction was observed between 82G/S polymorphisms with obesity (Pinteraction=0.028). Taking the non-obese 82GG genotype as references, the OR for OA in non-obese SS carriers was 2.537 (95% CI 1.241-5.189, P=0.001). Notably, the OR in obese GS carriers was 2.304 (95% CI: 1.218-4.357, P=0.009) and in obese SS was 3.392 (95% CI: 1.672-6.885, P=0.001). The -374T/A and -429T/C did not show positive interaction with obesity and smoking status.

CONCLUSION

The AGE 82G/S polymorphisms, in interaction with obesity, may determine the susceptibility of OA in Chinese population.

Receptor for advanced glycation end products (RAGE) polymorphisms are associated with systemic lupus erythematosus and disease severity in lupus nephritis

OBJECTIVE

Interaction of advanced glycation end products (AGEs) with their receptors (RAGE) plays an important role in inflammation in auto-immune diseases. Several functional polymorphisms of RAGE have been described. In this study we analysed the role of RAGE polymorphisms in disease susceptibility for systemic lupus erythematosus (SLE). In addition, we investigated whether these polymorphisms in SLE are associated with serum levels of soluble RAGE (sRAGE), renal involvement (lupus nephritis (LN)) and its outcome.

METHODS

For this cross-sectional study DNA samples of 97 SLE patients, 114 LN patients and 429 healthy controls (HC) were genotyped for four RAGE polymorphisms: -429 T/C, -374 T/A, 2184 A/G and Gly82Ser. Differences in genotype frequencies and allele frequencies were tested between patients and HCs. In SLE patients, sRAGE was measured by enzyme-linked immunosorbent assay (ELISA). In addition, association of genotypes with sRAGE and disease severity in LN was analysed.

RESULTS

The C allele of -429 T/C, the T allele of -374 T/A and the G allele of 2184 A/G were significantly more prevalent in SLE and LN compared with HC. In LN, the C allele of RAGE -429 T/C, the A allele of -374 T/A and the G allele of RAGE 2184 A/G polymorphism were significantly associated with more proteinuria and worse renal function during the first two years of treatment. No association of genotype with sRAGE was found.

CONCLUSION

RAGE polymorphisms are associated with susceptibility to SLE and LN. In addition, some of these polymorphisms are likely to be associated with disease severity and initial response to treatment in LN.

Soluble receptor for AGE (RAGE) is a novel independent predictor of all-cause and cardiovascular mortality in type 1 diabetes

AIMS/HYPOTHESIS

Activation of the receptor for AGE (RAGE) is implicated in the development and progression of vascular complications of diabetes. In this study, we explore factors and mortality outcomes associated with soluble RAGE (sRAGE) in a multicentre nationwide cohort of Finnish adults with type 1 diabetes.

METHODS

Baseline sRAGE concentrations were estimated in 3,100 adults with type 1 diabetes. Clinical and biological variables independently associated with sRAGE were identified using multivariate regression analysis. Independent predictors of mortality were determined using Cox and Fine-Gray proportional-hazards models.

RESULTS

The main independent determinants of sRAGE concentrations were estimated glomerular filtration rate, albuminuria, body mass index, age, duration of diabetes, HbA(1c) and insulin dose (all p < 0.05). During a median of 9.1 years of follow-up there were 202 deaths (7.4 per 1,000 patient years). sRAGE was independently associated with all-cause (Cox model: HR 1.03) and cardiovascular mortality (Fine-Gray competing risks model: HR 1.06) such that patients with the highest sRAGE concentrations had the greatest risk of mortality, after adjusting for age, sex, macrovascular disease, HDL-cholesterol, HbA(1c), triacylglycerol, high-sensitivity C-reactive protein (hsCRP) and the presence and severity of chronic kidney disease. Although polymorphisms in the gene coding for RAGE were significantly associated with sRAGE concentrations, none were associated with mortality outcomes.

CONCLUSIONS/INTERPRETATION

Increased concentrations of sRAGE are associated with increased all-cause and cardiovascular mortality in type 1 diabetes, potentially reflecting the activation and production of RAGE in the context of accelerated vascular disease. These novel findings highlight the importance of the RAGE activation in the prevention and management of diabetic complications.

Receptor for advanced glycation end-products (RAGE) provides a link between genetic susceptibility and environmental factors in type 1 diabetes

AIMS/HYPOTHESIS

This group of studies examines human genetic susceptibility conferred by the receptor for advanced glycation end-products (RAGE) in type 1 diabetes and investigates how this may interact with a western environment.

METHODS

We analysed the AGER gene, using 13 tag SNPs, in 3,624 Finnish individuals from the FinnDiane study, followed by AGER associations with a high risk HLA genotype (DR3)-DQA1*05-DQB1*02/DRB1*0401-DQB1*0302 (n = 546; HLA-DR3/DR4), matched in healthy newborn infants from the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Study (n = 373) using allelic analysis. We also studied islets and circulating RAGE in NODLt mice.

RESULTS

The rs2070600 and rs17493811 polymorphisms predicted increased risk of type 1 diabetes, whereas the rs9469089 SNP was related to decreased risk, on a high risk HLA background. Children from the DIPP study also showed a decline in circulating soluble RAGE levels, at seroconversion to positivity for type 1 diabetes-associated autoantibodies. Islet RAGE and circulating soluble RAGE levels in prediabetic NODLt mice decreased over time and were prevented by the AGE lowering therapy alagebrium chloride. Alagebrium chloride also decreased the incidence of autoimmune diabetes and restored islet RAGE levels.

CONCLUSIONS/INTERPRETATION

These studies suggest that inherited AGER gene polymorphisms may confer susceptibility to environmental insults. Declining circulating levels of soluble RAGE, before the development of overt diabetes, may also be predictive of clinical disease in children with high to medium risk HLA II backgrounds and this possibility warrants further investigation in a larger cohort.

The G82S polymorphism promotes glycosylation of the receptor for advanced glycation end products (RAGE) at asparagine 81: comparison of wild-type rage with the G82S polymorphic variant

Interaction between the receptor for advanced glycation end products (RAGE) and its ligands amplifies the proinflammatory response. N-Linked glycosylation of RAGE plays an important role in the regulation of ligand binding. Two potential sites for N-linked glycosylation, at Asn(25) and Asn(81), are implicated, one of which is potentially influenced by a naturally occurring polymorphism that substitutes Gly(82) with Ser. This G82S polymorphic RAGE variant displays increased ligand binding and downstream signaling. We hypothesized that the G82S polymorphism affects RAGE glycosylation and thereby affects ligand binding. WT or various mutant forms of RAGE protein, including N25Q, N81Q, N25Q/G82S, and N25Q/N81Q, were produced by transfecting HEK293 cells. The glycosylation patterns of expressed proteins were compared. Enzymatic deglycosylation showed that WT RAGE and the G82S polymorphic variant are glycosylated to the same extent. Our data also revealed N-linked glycosylation of N25Q and N81Q mutants, suggesting that both Asn(25) and Asn(81) can be utilized for N-linked glycosylation. Using mass spectrometry analysis, we found that Asn(81) may or may not be glycosylated in WT RAGE, whereas in G82S RAGE, Asn(81) is always glycosylated. Furthermore, RAGE binding to S100B ligand is affected by Asn(81) glycosylation, with consequences for NF-κB activation. Therefore, the G82S polymorphism promotes N-linked glycosylation of Asn(81), which has implications for the structure of the ligand binding region of RAGE and might explain the enhanced function associated with the G82S polymorphic RAGE variant.

A functional p.82G>S polymorphism in the RAGE gene is associated with multiple sclerosis in the Chinese population

BACKGROUND

The receptor for advanced glycation end products (RAGE) and its proinflammatory ligand, S100-calgranulins, are critically implicated in the pathological progression of multiple sclerosis (MS). A functional polymorphism within the V-type immunoglobulin domain of RAGE gene, p.82G>S (c.557G>A), has been shown to affect ligand binding affinity and thus may affect susceptibility to MS.

METHODS

The RAGE p.82G>S polymorphism was genotyped in 144 MS patients and 156 healthy controls using polymerase chain reaction - restriction fragment length polymorphism. A replication study was performed on a second cohort comprising 138 patients and 150 controls. The relationship between the RAGE p.82G>S polymorphism and circulating levels of soluble RAGE (sRAGE), a secreted decoy receptor against RAGE signaling, was also investigated.

RESULTS

In both initial and replication cohorts, an increased MS risk was detected in RAGE p.82G>S variant allele carriers (odds ratio [OR] = 1.786, p = 0.0134 and OR = 1.732, p = 0.0210, respectively). This association signal persisted in subgroups of women and patients with relapsing-remitting MS. Moreover, compared with the wild-type 82GG carriers, carriers of the variant allele presented a faster progression of disability and a reduced serum sRAGE level.

CONCLUSIONS

The present study provides preliminary evidence that the gain-of-function p.82G>S polymorphism in the RAGE gene is associated with an increased risk of MS in the Chinese population.

Association of serum soluble receptor for advanced glycation end-products with subclinical cerebrovascular disease: the Northern Manhattan Study (NOMAS)

OBJECTIVE

Serum levels of the soluble receptor for advanced glycation end-products (sRAGE) have been associated with risk of cardiovascular disease. We hypothesized that sRAGE levels are associated with subclinical cerebrovascular disease in an ethnically diverse population.

METHODS

Clinically stroke-free participants in the multi-ethnic Northern Manhattan Study (NOMAS) underwent brain MRI to quantify subclinical brain infarcts (SBI) and white matter hyperintensity volume (WMHV) (n = 1102). Serum levels of sRAGE were measured by ELISA. Logistic and multiple linear regression were employed to estimate associations of sRAGE with SBI and WMHV, after adjusting for demographics and vascular risk factors.

RESULTS

Median sRAGE levels were significantly lower in Hispanics (891.9 pg/ml; n = 708) and non-Hispanic blacks (757.4 pg/ml; n = 197) than in non-Hispanic whites (1120.5 pg/ml; n = 170), and these differences remained after adjusting for other risk factors. Interactions were observed by race-ethnicity between sRAGE levels and MRI measurements, including for SBI in Hispanics (p = 0.04) and WMHV among blacks (p = 0.03). In Hispanics, increasing sRAGE levels were associated with a lower odds of SBI, with those in the upper sRAGE quartile displaying a 50% lower odds of SBI after adjusting for sociodemographic and vascular risk factors (p = 0.05). Among blacks, those in the upper quartile of sRAGE had a similarly reduced increased risk of SBI (p = 0.06) and greater WMHV (p = 0.04).

CONCLUSION

Compared to whites, Hispanics and blacks have significantly lower sRAGE levels, and these levels were associated with more subclinical brain disease. Taken together, these findings suggest sRAGE levels may be significantly influence by ethnicity. Further studies of sRAGE and stroke risk, particularly in minorities, are warranted.

Association of polymorphisms in the RAGE gene with serum CRP levels and coronary artery disease in the Chinese Han population

The role of an advanced glycation end product/receptor for advanced glycation end product (AGE/RAGE) system in the pathogenesis of coronary artery disease (CAD) is not fully understood. To clarify whether polymorphisms of the RAGE gene were related to CAD, we performed a case-control study in Chinese Han patients. The allele frequencies and genotype distribution combinations of the -429T/C, 1704G/T and G82S polymorphisms of the RAGE gene were compared in 200 cases of hypertension (HT), 155 cases of CAD combined with HT (CAD&HT), 175 cases of CAD and 170 control subjects. Polymerase chain reaction-restriction fragment length polymorphism was used for detection of genotypic variants. The S allele frequency of the G82S polymorphism was higher in the CAD (odds ratio (OR), 2.303, 95% confidence interval (CI) 1.553-3.416; P<0.001, P(corr)<0.003) and CAD&HT (OR, 1.842; 95% CI 1.219-2.785; P<0.003, P(corr)<0.009) groups when compared with the control group. However, the S allele frequency was not significantly different between the CAD and the CAD&HT patient groups (P=0.223), and no statistically significant difference of genotype or allele frequency distributions was observed in the HT group (P>0.05). Meanwhile, serum CRP was significantly associated with the G82S variant. Haplotype-based logistic regression analysis revealed that haplotype G-Ser-T (OR, 1.670; 95% CI, 1.017-2.740; P=0.043), compared with the reference haplotype T-Gly-T, was associated with an increased risk of CAD after adjusting for other risk factors. Further analysis limited to non-diabetic participants exhibited similar significant findings. The haplotype carrying the G82S variant of the RAGE gene was significantly associated with an increased risk of CAD, but not with HT patients. Moreover, a remarkable association of the G82S variant with serum CRP levels implied that the prevalence of RAGE 82S allelic variation might influence susceptibility to CAD by affecting vascular inflammation.

Association of the RAGE G82S polymorphism with Alzheimer's disease

The receptor for advanced glycation end-products (RAGE) has been implicated in several pathophysiological processes relevant to Alzheimer’s disease (AD), including transport and synaptotoxicity of AD-associated amyloid β (Aβ) peptides. A recent Chinese study (Li et al. in J Neural Transm 117:97–104, 2010) suggested an association between the 82S allele of the functional single nucleotide polymorphism (SNP) G82S (rs2070600) in the RAGE-encoding gene AGER and risk of AD. The present study aimed to investigate associations between AGER, AD diagnosis, cognitive scores and cerebrospinal fluid AD biomarkers in a European cohort of 316 neurochemically verified AD cases and 579 controls. Aside from G82S, three additional tag SNPs were analyzed to cover the common genetic variation in AGER. The 82S allele was associated with increased risk of AD (P_c = 0.04, OR = 2.0, 95% CI 1.2–3.4). There was no genetic interaction between AGER 82S and APOE ε4 in producing increased risk of AD (P = 0.4), and none of the AGER SNPs showed association with Aβ₄₂, T-tau, P-tau₁₈₁ or mini-mental state examination scores. The data speak for a weak, but significant effect of AGER on risk of AD.

High plasma levels of the soluble receptor for advanced glycation endproducts in patients with symptomatic carotid atherosclerosis

BACKGROUND

Advanced glycation endproducts (AGEs), particularly carboxymethyl(lysine)-adducts (CML), exert part of their cellular effects by binding to a receptor, named receptor for AGEs (RAGE). The soluble form of this receptor (sRAGE) has been shown to have an athero-protective role. We hypothesized the existence of a relationship between the AGE-RAGE axis and the occurrence of symptoms related to carotid atherosclerosis in nondiabetic conditions.

MATERIALS AND METHODS

We evaluated plasma levels of CML and sRAGE (by ELISA), and tissue levels (tAGEs and tRAGE, semiquantitatively, by immunohistochemistry) in endarterectomy carotid plaque tissue in 29 nondiabetic patients. At the time of surgery, 10 patients were asymptomatic and 19 were symptomatic.

RESULTS

Plasma levels of sRAGE were higher in symptomatic patients than in asymptomatic patients [median (interquartile range): 676 (394-858) pg mL(-1) vs. 347 (284-479) pg mL(-1), P = 0.009]. In symptomatic patients, plasma levels of sRAGE correlated positively with CML (r = 0.60, P < 0.01), C-reactive protein (CRP) (r = 0.618, P < 0.01) and fibrinogen (r = 0.522, P<0.005), while in asymptomatic patients, no correlation was observed. Although tissue and plasma levels of AGEs and RAGE did not correlate between each other, tAGEs and tRAGE were also positively correlated only in symptomatic patients (chi(2) = 8.93, P = 0.003).

CONCLUSIONS

Plasma levels of sRAGE are higher in symptomatic than asymptomatic carotid atherosclerosis. Higher levels of sRAGE in symptomatic patients may be markers of a higher degree of vascular inflammation in such patients.

Soluble forms of RAGE in internal medicine

The receptor for advanced glycation end-products (RAGE) and its ligands are intimately involved in the pathobiology of a wide range of diseases that share common features, such as enhanced oxidative stress, immune/inflammatory responses, and altered cell functions. Soluble forms of RAGE (sRAGE), including the splice variant endogenous secretory (es)RAGE, have been found circulating in plasma and tissues. Experimental data suggest that these isoforms may neutralize the ligand-mediated damage by acting as a decoy. Moreover, evidence is mounting to support a role for both sRAGE and esRAGE as biomarkers or endogenous protection factors against RAGE-mediated pathogenesis. In this review, we will focus on clinical and therapeutical implications arising from studies investigating the significance of soluble RAGE isoforms in several clinical settings, including cardiovascular disease, diabetes mellitus, hypercholesterolemia, chronic renal failure, immune/inflammatory diseases, pulmonary diseases, neurodegeneration, and cancer.

G allele at RAGE SNP82 is associated with proinflammatory markers in obese subjects

Obesity is closely associated with low-grade inflammation. The Gly82Ser (G82S) polymorphism in the receptor for the advanced glycation end products (RAGE) gene related to RAGE expression is also involved in inflammatory response. We examined the association between RAGEG82S and obesity on soluble RAGE (sRAGE) and inflammatory markers in Korean men. The following were measured: anthropometric and biochemical parameters, RAGEG82S polymorphism, sRAGE, advanced glycation end products (AGEs), and inflammatory markers in men (n = 1252; range, 30-70 years; body mass index [BMI], > or =18.5 kg/m(2)). Allele frequencies satisfied Hardy-Weinberg Equilibrium (G/G: 72.2%, G/S: 25.5%, S/S: 2.3%). RAGEG82S (beta-coefficient = -0.384, P < .001) and BMI (beta-coefficient = -0.168, P = .001) were major factors affecting sRAGE concentrations. In all subjects, those with 'S/S' homozygotes showed the lowest levels of sRAGE (G/G: 1036.3 +/- 40.3, G/S: 807.0 +/- 49.6, S/S: 443.0 +/- 47.8 pg/mL) before (P < .001) and after adjusted for age, BMI, cigarette smoking, and alcohol drinking (P < .001). When subdivided according to BMI of 25 kg/m(2) (Asian Pacific guideline), obese subjects (BMI > or =25 kg/m(2)) had significantly lower levels of sRAGE (831.7 +/- 36.7 vs 1022.7 +/- 47.8 pg/mL, P = .009) and higher levels of high sensitivity C-reactive protein (hs-CRP) (1.10 +/- 0.07 vs 0.72 +/- 0.05 mg/dL, P < .001) compared with nonobese subjects (BMI <25 kg/m(2)). Particularly in obese subjects, S/S carriers showed significantly higher concentrations of AGEs (P = .012) and hs-CRP (P = .006) than G allele carriers, whereas nonobese people had no significant RAGEG82S-related differences in AGEs (P = .743) and hs-CRP (P = .436). In conclusion, G allele at RAGEG82S may be more associated with inflammatory markers under obese status than nonobese conditions. In this case, it may help to suggest proper dietary modification for controlling obesity to people with genetic variants.

Decreased serum esRAGE level is associated with angiographically determined coronary plaque progression in diabetic patients

OBJECTIVE

This study evaluated the relationship between serum levels of endogenous secretory receptor for advanced glycation endproducts (esRAGE) and coronary plaque progression in diabetic and nondiabetic patients.

DESIGN AND METHODS

Serum esRAGE level was measured and quantitative coronary angiography (QCA) was performed in 265 consecutive patients at baseline and 1-year follow-up.

RESULTS

Comparing to baseline, serum esRAGE level was significantly increased during follow-up in nondiabetic patients without plaque progression (p=0.014), unchanged in nondiabetic patients with plaque progression and diabetic patients without plaque progression, and decreased in diabetic patients with plaque progression (p=0.011). Moreover, change of esRAGE levels correlated with change of QCA measurements. Multivariable regression analyses revealed that high-density lipoprotein cholesterol (OR=0.214, p=0.037), hypertension (OR=2.755, p=0.011), high-sensitivity C-reactive protein (OR=1.083, p<0.001) and change of esRAGE (OR=23.477, p<0.001) were independent risk factors for plaque progression in diabetic patients.

CONCLUSIONS

This study demonstrated an association of decreased serum esRAGE level with coronary plaque progression in patients with diabetes.

Detection of feto-maternal infection/inflammation by the soluble receptor for advanced glycation end products (sRAGE): results of a pilot study

OBJECTIVE

The receptor for advanced glycation end products, RAGE, plays an important role in the pathogenesis of several diseases. sRAGE, soluble receptor for advanced glycation end products, is an inhibitor of the pathological effect mediated via RAGE. The aim of this study was to assess the usefulness of measuring sRAGE concentration in pregnant women with threatening preterm labor.

METHODS

Serum levels of sRAGE, interleukin-6 (IL-6) and routine markers of inflammation were determined in 46 pregnant women with threatening preterm labor, 35 healthy pregnant women and 15 non-pregnant controls.

RESULTS

Serum levels of sRAGE in healthy pregnant women were significantly lower than in non-pregnant controls (669+/-296 vs. 1929+/-727 pg/mL, P<0.05). Women with threatening preterm birth had a significantly higher concentration of serum sRAGE in comparison with healthy pregnant women (819+/-329 pg/mL vs. 669+/-296 pg/mL, P<0.05). Conversely, patients with PPROM had significantly lower levels of sRAGE compared with patients with threatening premature labor (600+/-324 pg/mL, P<0.05). sRAGE correlated negatively with leukocyte counts (r=-0.325, P<0.05).

CONCLUSIONS

sRAGE might be a new and promising marker of premature labor, especially with the symptoms of PPROM.

Gly82Ser polymorphism of the receptor for advanced glycation end products is associated with an increased risk of gastric cancer in a Chinese population

PURPOSE

It has been shown that the expression of the receptor for advanced glycation end products (RAGE) is closely associated with invasion and metastasis in gastric cancer. A Gly82Ser polymorphism in exon 3 of RAGE gene was identified and thought to have an effect on the functions of its protein. Therefore, the goal of the present study was to investigate whether the polymorphism is involved in the development or progression of gastric cancer.

EXPERIMENTAL DESIGN

In the hospital-based case-control study, the RAGE genotypes were determined using PCR-RFLP in 566 individuals (283 gastric cancer patients and 283 age- and sex-matched controls).

RESULTS

The distribution of genotype was significantly different between cases and controls (P = 0.038). Compared with the wild-type 82Gly/Gly carriers, subjects with the variant genotypes (82Gly/Ser and 82Ser/Ser) had a significantly higher risk of gastric cancer (adjusted odds ratio, 1.47; 95% confidence interval, 1.05-2.06). Moreover, the elevated gastric cancer risk was especially evident in younger individuals (ages < or =58 years), nonsmokers, and rural subjects. Further analyses revealed that the variant genotypes were associated with adjacent organ invasion in the subanalysis of gastric cancer patients.

CONCLUSIONS

Our findings indicate that the RAGE Gly82Ser polymorphism may confer not only an increased risk of gastric cancer but also with invasion of gastric cancer in the Chinese population.

Soluble Receptor for advanced glycation end products (RAGE) is a prognostic factor for heart failure

BACKGROUND

We recently reported that serum levels of pentosidine, one of the well-defined advanced glycation end products (AGE), was an independent prognostic factor for heart failure. Receptor for AGEs (RAGE) is expressed in a variety of tissues, and RAGE has a C-truncated secretory isoform of the receptor protein, termed soluble RAGE. In the present study, we measured serum soluble RAGE levels in patients and examined whether serum soluble RAGE predicts prognosis in patients with heart failure.

METHODS AND RESULTS

Serum soluble RAGE concentration was measured in 160 patients with heart failure by a competitive enzyme-linked immunosorbent assay. Patients were prospectively followed during a median follow-up period of 872 days with end points of cardiac death or rehospitalization. Serum soluble RAGE level increased with advancing New York Heart Association functional class. Serum soluble RAGE level was also higher in patients with cardiac events than in event free patients. From the receiver operating characteristic curve analysis, the cutoff value of serum soluble RAGE level was determined as 1220 pg/mL. Kaplan-Meier analysis clearly demonstrated that the high soluble RAGE group had a significantly higher incidence of cardiac events than occurred in the low serum soluble RAGE group (P = .0004). In the multivariate Cox proportional hazard analysis, soluble RAGE and serum pentosidine were independent risk factors for cardiac events (soluble RAGE: HR 1.90, 95% CI 1.16-3.09, P = .010; pentosidine: HR 1.59, 95% CI 1.11-2.29, P = .012).

CONCLUSIONS

Serum soluble RAGE level is an independent prognostic factor for heart failure, and this novel marker may be useful for risk stratification of patients with heart failure.

Dietary fructose and the metabolic syndrome

PURPOSE OF REVIEW

Fructose, a naturally found sugar in many fruits, is now commonly used as an industrial sweetener and is excessively consumed in Western diets. High fructose intake is increasingly recognized as causative in development of prediabetes and metabolic syndrome. The mechanisms underlying fructose-induced metabolic disturbances are unclear but are beginning to be unravelled. This review presents recent findings in this field and an overall mechanistic insight into the metabolic effects of dietary fructose and its role in metabolic syndrome.

RECENT FINDINGS

Recent animal studies have confirmed the link between fructose feeding and increased plasma uric acid, a potentially causative factor in metabolic syndrome. Advanced glycation end products are also implicated because of their direct protein modifications and indirect effects on inflammation and oxidative stress. Human studies have demonstrated fructose's ability to change metabolic hormonal response, possibly contributing to decreased satiety.

SUMMARY

There is much evidence from both animal models and human studies supporting the notion that fructose is a highly lipogenic nutrient that, when consumed in high quantities, contributes to tissue insulin insensitivity, metabolic defects, and the development of a prediabetic state. Recently evidence has helped to decipher the mechanisms involved in these metabolic changes.