scholarly journals Advanced Glycation End Products: Formation, Role in Diabetic Complications, and Potential in Clinical Applications

2020 ◽  
Author(s):  
Rujman Khan ◽  
Xin Yee Ooi ◽  
Matthew Parvus ◽  
Laura Valdez ◽  
Andrew Tsin
Keyword(s):  
Diabetic Retinopathy ◽  
Advanced Glycation End Products ◽  
Diabetic Complications ◽  
Tanshinone Iia ◽  
Future Research ◽  
Advanced Glycation ◽  
Reactive Aldehydes ◽  
Glycation End Products ◽  
End Products ◽  
Lysine Residues

Hyperglycemic conditions and disruptions to glucose-regulating pathways lead to increased formation of highly reactive aldehydes, methylglyoxal and glyoxal, which react with certain arginine and lysine residues in proteins to form advanced glycation end products (AGEs). These AGEs damage the integrity of the retinal vasculature predominantly through two mechanisms: non-receptor-mediated damage, which pertains to the interaction with extracellular matrix and its functional properties, and receptor-mediated damage through AGE interactions with their receptors (RAGE) on pericytes and Muller cells. Damage occurring between AGE and RAGE potentially generates reactive oxygen species, inflammatory cytokines, and growth factors. Both mechanisms result in increased permeability of endothelial tight junctions, and this increased permeability can lead to leaking and eventually ischemia. Once this ischemia becomes significant, neovascularization can occur, the hallmark of proliferative diabetic retinopathy. Current pharmaceutical studies have shown the potential of AGE inhibitors, such as aminoguanidine, in decreasing AGE production, thus minimizing its effects in hyperglycemic conditions. Other pharmaceutical interventions, such as Tanshinone IIA, aim to protect cells from the impacts of AGEs. Future research will not only continue to understand the properties of AGEs and their effects on diabetes and diabetic complications like diabetic retinopathy but will also explore how they impact other diseases.

scholarly journals N ε-(Carboxyethyl)lysine, a product of the chemical modification of proteins by methylglyoxal, increases with age in human lens proteins

1997 ◽  
Vol 324 (2) ◽  
pp. 565-570 ◽  
Author(s):  
Mahtab U. AHMED ◽  
Elisabeth BRINKMANN FRYE ◽  
Thorsten P. DEGENHARDT ◽  
Suzanne R. THORPE ◽  
John W. BAYNES
Keyword(s):  
Advanced Glycation End Products ◽  
Human Lens ◽  
Advanced Glycation ◽  
Model Compounds ◽  
Lens Proteins ◽  
Glycation End Products ◽  
End Products ◽  
Lysine Residues ◽  
Carboxymethyl Lysine ◽  
Chemical Modification Of Proteins

Advanced glycation end-products and glycoxidation products, such as Nϵ-(carboxymethyl)lysine (CML) and pentosidine, accumulate in long-lived tissue proteins with age and are implicated in the aging of tissue proteins and in the development of pathology in diabetes, atherosclerosis and other diseases. In this paper we describe a new advanced glycation end-product, Nϵ-(carboxyethyl)lysine (CEL), which is formed during the reaction of methylglyoxal with lysine residues in model compounds and in the proteins RNase and collagen. CEL was also detected in human lens proteins at a concentration similar to that of CML, and increased with age in parallel with the concentration of CML. Although CEL was formed in highest yields during the reaction of methylglyoxal and triose phosphates with lysine and protein, it was also formed in reactions of pentoses, ascorbate and other sugars with lysine and RNase. We propose that levels of CML and CEL and their ratio to one another in tissue proteins and in urine will provide an index of glyoxal and methylglyoxal concentrations in tissues, alterations in glutathione homoeostasis and dicarbonyl metabolism in disease, and sources of advanced glycation end-products in tissue proteins in aging and disease.

scholarly journals Association of the Receptor for Advanced Glycation End Products Gene Polymorphisms and Circulating RAGE Levels with Diabetic Retinopathy in the Chinese Population

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Li Yang ◽  
Qunhong Wu ◽  
Yuan Li ◽  
Xiaohong Fan ◽  
Yanhua Hao ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Advanced Glycation End Products ◽  
Chinese Population ◽  
Genetic Interaction ◽  
Interaction Model ◽  
Serum Levels ◽  
Advanced Glycation ◽  
Soluble Rage ◽  
Glycation End Products ◽  
End Products

Objectives. This study investigated the association between polymorphisms in the receptor for advanced glycation end products (RAGE) gene and the susceptibility to diabetic retinopathy (DR) in a Chinese population and identified a correlation between serum-soluble RAGE (sRAGE) levels and DR risk.Materials and Methods. We enrolled 1040 patients with type 2 diabetes mellitus: 372 patients with DR and 668 without retinopathy (NDR). All polymorphisms were genotyped by time-of-flight mass spectrometry. Serum levels of sRAGE were assayed by enzyme-linked immunosorbent assays. The interaction of SNPs was analyzed by multifactor dimensionality reduction (MDR).Results. The frequency of the SS genotype for the G82S polymorphism was 12.4% in the DR group and 6.6% in the NDR group; this difference was significant. G82S was associated with sRAGE levels. Specifically, after adjustments for age, sex, duration, and glucose metabolism, serum sRAGE levels were significantly higher in DR subjects with the S/S genotype than in NDR subjects in general. In the DR group, subjects with the G/S genotype had lower sRAGE levels than subjects with the G/G or S/S genotype (P<0.01). The best multilocus genetic interaction model was assessed using the MDR method; 2184A/G, 1704G/T, G82S, and −429T/C were identified.Conclusions. The findings suggest that the G82S polymorphism in theRAGEgene is associated with DR risk, and G82S was associated with circulating levels of sRAGE. The mechanism by which G82S polymorphism modulates the sRAGE levels remains to be elucidated.

Monocyte CD147 is induced by advanced glycation end products and high glucose concentration: possible role in diabetic complications

2010 ◽  
Vol 299 (5) ◽  
pp. C1212-C1219 ◽  
Author(s):  
W. Bao ◽  
D. Min ◽  
S. M. Twigg ◽  
N. A. Shackel ◽  
F. J. Warner ◽  
...  
Keyword(s):  
Advanced Glycation End Products ◽  
Diabetic Complications ◽  
High Glucose ◽  
Transmembrane Protein ◽  
Soluble Form ◽  
Dependent Manner ◽  
Advanced Glycation ◽  
Glycation End Products ◽  
End Products ◽  
Cd147 Expression

CD147 is a highly glycosylated transmembrane protein that is known to play a role in regulation of many protein families. It has the unique ability to maintain functional activity in both the membrane bound state and in the soluble form. CD147 is known to play a role in regulation of matrix metalloproteinase (MMP) expression, but whether its expression is affected by the diabetic milieu is not known, and its role in regulation of monocyte MMPs in this environment has not been investigated. Therefore, in this study we investigated the effect of advanced glycation end products (AGEs) and high glucose (HG; 25 mM), on monocyte CD147 expression. Culture of THP-1 monocytes in the presence of AGEs or HG significantly increased CD147 at the gene and protein level. THP-1 cell results were confirmed using freshly isolated monocytes from human volunteers. The effect of AGEs and HG on CD147 expression was also mimicked by addition of proinflammatory cytokines. Addition of AGEs or HG also increased expression of monocyte MMP-1 and MMP-9 but not MMP-2. This increase in MMPs was significantly attenuated by inhibition of CD147 using either a small interfering RNA or an anti-CD147 antibody. Inhibition of NF-κB or addition of antibodies to either TNF-α or the receptor for AGE (RAGE) each significantly prevented in a dose-dependent manner the induction of CD147 gene and protein by AGE and also decreased MMP-1 and MMP-9. This novel result shows that AGEs can induce monocyte CD147 expression, an effect mediated by inflammatory pathways and RAGE. Because MMPs play a role in monocyte migration, inhibition of their regulator CD147 may assist in the prevention of diabetic complications, particularly those where monocyte infiltration is an early initiating event.

Advanced glycation end products and diabetic retinopathy

Amino Acids ◽  
2011 ◽  
Vol 44 (6) ◽  
pp. 1397-1407 ◽  
Author(s):  
Ross Milne ◽  
Seymour Brownstein
Keyword(s):  
Diabetic Retinopathy ◽  
Advanced Glycation End Products ◽  
Advanced Glycation ◽  
Glycation End Products ◽  
End Products
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