Genetic Variants of the Receptor for Advanced Glycation End-products in Susceptibility to Type 2 Diabetes Mellitus in Primary Hypertensive Patients

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.

Hypertension and diabetes mellitus: highlights of a complex relationship

PURPOSE OF REVIEW

Herein, we provide a review of the recent literature on the epidemiological and pathophysiological relationship between hypertension (HTN) and diabetes mellitus, along with prognostic implications and current treatment concepts.

RECENT FINDINGS

Diabetes mellitus affects ∼10% of US adults. The prevalence of HTN in adults with diabetes mellitus was 76.3% or 66.0% based on the definitions used by guidelines. There exist differences among major society guidelines regarding the definition of HTN and target blood pressure (BP) levels. Recent basic and clinical research studies have shed light on pathophysiologic and genetic links between HTN and diabetes mellitus. Randomized controlled trials over the past 5 years have confirmed the favorable BP and cardiovascular risk reduction by antidiabetic agents.

SUMMARY

HTN and diabetes mellitus are 'silent killers' with rising global prevalence. The development of HTN and diabetes mellitus tracks each other over time. The coexistence of both clinical entities synergistically contributes to micro- and macro-vasculopathy along with cardiovascular and all-cause mortality. Various shared mechanisms underlie the pathophysiological relationship between HTN and diabetes mellitus. Moreover, BP reduction with lifestyle interventions and antihypertensive agents is a primary target for reducing cardiovascular risk among patients with HTN and diabetes mellitus.

RAGE and its ligands: from pathogenesis to therapeutics

Receptor for advanced glycation end products (RAGE) is an immunoglobulin-like receptor present on cell surface. RAGE binds to an array of structurally diverse ligands, acts as a pattern recognition receptor (PRR) and is expressed on cells of different origin performing different functions. RAGE ligation leads to the initiation of a cascade of signaling events and is implicated in diseases, such as inflammation, cancer, diabetes, vascular dysfunctions, retinopathy, and neurodegenerative diseases. Because of the significant involvement of RAGE in the progression of numerous diseases, RAGE signaling has been targeted through use of inhibitors and anti-RAGE antibodies as a treatment strategy and therapy. Here in this review, we have summarized the physical and physiological aspects of RAGE biology in mammalian system and the importance of targeting this molecule in the treatment of various RAGE mediated pathologies. Highlights Receptor for advanced glycation end products (RAGE) is a member of immunoglobulin superfamily of receptors and involved in many pathophysiological conditions. RAGE ligation with its ligands leads to initiation of distinct signaling cascades and activation of numerous transcription factors. Targeting RAGE signaling through inhibitors and anti-RAGE antibodies can be promising treatment strategy.

Genetic Association of SH2B1 Gene Polymorphisms in Jordanian Arab Patients with Type 2 Diabetes Mellitus

OBJECTIVE

To investigate the genotypic and allelic association of Src homology 2 B adapter protein 1 (SH2B1) gene polymorphisms with type 2 diabetes mellitus (T2DM) in Jordanian patients.

PATIENTS AND METHODS

Three hundred patients were screened, but only 200 adult Jordanian patients diagnosed with T2DM (53.5% male and 46.5% female) have participated in this study. Blood samples were collected from both patients and healthy individuals for DNA extraction according to well-established procedures. Exon 1 and exon 9 of the SH2B1 gene were sequenced using an efficient and sensitive DNA sequencing method in order to identify specific single nucleotide polymorphisms (SNPs) in the SH2B1 gene associated with T2DM. Genetic and haplotype correlation analysis was performed for the chosen SNPs to detect any association if existent. In addition, SNPStats Web Tool and Hardy-Weinberg equilibrium (HWE) analyses for the genotype distribution were used. The significance was determined according to the P-value, and the level of significance taken as P < 0.05. The normality of the data distribution was statically analysed by the Shapiro-Wilk test with a P-value >0.05. Also, the patient's characteristics and clinical data about all participants were mentioned.

RESULTS

Two novel variations were present in the SH2B1 gene in Jordanian patients with T2DM: c.827C>G and c.2026G>A, and previously reported five SNPs: rs146946750, rs565131715, rs370302573, rs143212778, rs200470848. Our results showed a strong genetic association of rs565131715 SNP polymorphism within the SH2B1 gene in T2DM patients (χ ² test, P < 0.001). Additionally, rs143212778 SNP presented a genetic correlation with T2DM patients (χ ² test, P = 0.035) as compared to control individuals. GTACG haplotype of SH2B1 has a highly significant association with responders (P< 0.0001).

CONCLUSION

Our findings indicated a strong association between the rs565131715 polymorphism and the risk of T2DM among the Jordanian population. Moreover, our data showed that the rs143212778 polymorphism significantly elevated the danger of T2DM among this population. This study reveals the first data regarding the SH2B1 gene polymorphisms in Jordanian patients of Arab descent with diabetes.

Metformin suppresses aortic ultrastrucural damage and hypertension induced by diabetes: a potential role of advanced glycation end products

Cardiovascular disease secondary to diabetes represents a significant challenge to the health community. The advanced glycation end products (AGEs) play an important role in diabetes-mediated vascular injury. We tested whether metformin can suppress aortic AGEs production and protect against aortic injuries (aortopathy) and hypertension in streptozotocin-induced type 2 diabetes mellitus (T2DM) animal model. T2DM was induced in rats two weeks after being fed on a high carbohydrate and fat diet (HCFD), and continued on a HCFD until being sacrificed at week 12 (model group). The protective group was put on metformin two weeks before diabetic induction and continued on metformin and HCFD until the end of the experiment, at week 12. Using electron microscopy examinations, we observed in the model group substantial damage to the ultrastructure of aortic endothelial and vascular smooth muscle layers as demonstrated by markedly distorted vacuolated endothelial and vascular smooth muscle cells with pyknotic nuclei detached from the underlying basement membrane, which were protected by metformin. Also, metformin significantly (p < .05) decreased both systolic and diastolic blood pressure, aortic levels of AGEs, and blood levels of oxidative stress and inflammatory biomarkers. We conclude that metformin protects against T2DM-induced aortopathy and hypertension, possibly via the inhibition of AGEs, inflammation, and oxidative stress.