Role of lipids in chemical modification of proteins and development of complications in diabetes

2003 ◽  
Vol 31 (6) ◽  
pp. 1413-1416 ◽  
Author(s):  
A.S. Januszewski ◽  
N.L. Alderson ◽  
T.O. Metz ◽  
S.R. Thorpe ◽  
J.W. Baynes

Hyperglycaemia is the major risk factor for the development of complications in both Type I and Type II diabetes; however, there is growing evidence from several clinical trials that dyslipidaemia, including hypertriglyceridaemia, is a significant and independent risk factor for diabetic complications. In this paper, we propose that chemical modification of proteins by lipids may be a underlying pathogenic mechanism linking dyslipidaemia to diabetic complications. Thus the major AGEs (advanced glycation end-products) in tissues, such as carboxymethyl-lysine, carboxyethyl-lysine and hydroimidazolones, may, in fact, be ALEs (advanced lipoxidation end-products), derived from lipids. Increased lipid peroxidation and accelerated ALE formation, possibly catalysed by hyperglycaemia and oxidative stress, may be the mechanistic link between dyslipidaemia and diabetic complications. If correct, this proposal would suggest that inhibition or reversal of glycation, which is a central theme of this symposium, may not be sufficient for protection against diabetic complications.

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 876
Author(s):  
Sara Chiappalupi ◽  
Laura Salvadori ◽  
Rosario Donato ◽  
Francesca Riuzzi ◽  
Guglielmo Sorci

The receptor for advanced glycation-end products (RAGE) is a multiligand receptor with a role in inflammatory and pulmonary pathologies. Hyperactivation of RAGE by its ligands has been reported to sustain inflammation and oxidative stress in common comorbidities of severe COVID-19. RAGE is essential to the deleterious effects of the renin–angiotensin system (RAS), which participates in infection and multiorgan injury in COVID-19 patients. Thus, RAGE might be a major player in severe COVID-19, and appears to be a useful therapeutic molecular target in infections by SARS-CoV-2. The role of RAGE gene polymorphisms in predisposing patients to severe COVID-19 is discussed. 


1997 ◽  
Vol 324 (2) ◽  
pp. 565-570 ◽  
Author(s):  
Mahtab U. AHMED ◽  
Elisabeth BRINKMANN FRYE ◽  
Thorsten P. DEGENHARDT ◽  
Suzanne R. THORPE ◽  
John W. BAYNES

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.


1998 ◽  
Vol 330 (1) ◽  
pp. 233-239 ◽  
Author(s):  
Shanlin FU ◽  
Min-Xin FU ◽  
W. John BAYNES ◽  
R. Suzanne THORPE ◽  
T. Roger DEAN

Glycation and subsequent Maillard or browning reactions of glycated proteins, leading to the formation of advanced glycation end products (AGEs), are involved in the chemical modification of proteins during normal aging and have been implicated in the pathogenesis of diabetic complications. Oxidative conditions accelerate the browning of proteins by glucose, and AGE proteins also induce oxidative stress responses in cells bearing AGE receptors. These observations have led to the hypothesis that glycation-induced pathology results from a cycle of oxidative stress, increased chemical modification of proteins via the Maillard reaction, and further AGE-dependent oxidative stress. Here we show that the preparation of AGE-collagen by incubation with glucose under oxidative conditions in vitro leads not only to glycation and formation of the glycoxidation product Nε-(carboxymethyl)lysine (CML), but also to the formation of amino acid oxidation products on protein, including m-tyrosine, dityrosine, dopa, and valine and leucine hydroperoxides. The formation of both CML and amino acid oxidation products was prevented by anaerobic, anti-oxidative conditions. Amino acid oxidation products were also formed when glycated collagen, prepared under anti-oxidative conditions, was allowed to incubate under aerobic conditions that led to the formation of CML. These experiments demonstrate that amino acid oxidation products are formed in proteins during glycoxidation reactions and suggest that reactive oxygen species formed by redox cycling of dopa or by the metal-catalysed decomposition of amino acid hydroperoxides, rather than by redox activity or reactive oxygen production by AGEs on protein, might contribute to the induction of oxidative stress by AGE proteins.


2008 ◽  
Vol 14 (10) ◽  
pp. 962-968 ◽  
Author(s):  
Sho-ichi Yamagishi ◽  
Seiji Ueda ◽  
Takanori Matsui ◽  
Kazuo Nakamura ◽  
Seiya Okuda

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1127
Author(s):  
Ivana Sirangelo ◽  
Margherita Borriello ◽  
Maria Liccardo ◽  
Marika Scafuro ◽  
Paola Russo ◽  
...  

Hydroxytyrosol (HT), the major phenolic compound in olive oil, is attracting increasing interest for its beneficial properties including a notable antioxidant and anti-inflammatory power. In this study, using a combination of biophysical and cell biology techniques, we have tested the role of HT in the formation of advanced glycation end-products (AGEs). AGEs have a key role in clinical sciences as they have been associated to diabetes, neurodegenerative and cardiovascular diseases. In addition, as the incidence of Alzheimer’s disease (AD) is strongly increased in diabetic patients, AGE formation is supposed to be involved in the development of the pathological hallmarks of AD. Our data show that HT selectively inhibits protein glycation reaction in human insulin, and it is able to counteract the AGE-induced cytotoxicity in human neurotypical cells by acting on SIRT1 level and oxidative stress, as well as on inflammatory response. This study identifies new beneficial properties for HT and suggests it might be a promising molecule in protecting against the AGE-induced toxicity, a key mechanism underlying the development and progression of neurodegenerative disorders.


Medicina ◽  
2019 ◽  
Vol 55 (10) ◽  
pp. 706 ◽  
Author(s):  
Cristina Iulia Mitran ◽  
Ilinca Nicolae ◽  
Mircea Tampa ◽  
Madalina Irina Mitran ◽  
Constantin Caruntu ◽  
...  

Background and objectives: Warts are the most common lesions caused by human papillomavirus (HPV). Recent research suggests that oxidative stress and inflammation are involved in the pathogenesis of HPV-related lesions. It has been shown that the soluble receptor for advanced glycation end products (sRAGE) may act as a protective factor against the deleterious effects of inflammation and oxidative stress, two interconnected processes. However, in HPV infection, the role of sRAGE, constitutively expressed in the skin, has not been investigated in previous studies. Materials and Methods: In order to analyze the role of sRAGE in warts, we investigated the link between sRAGE and the inflammatory response on one hand, and the relationship between sRAGE and the total oxidant/antioxidant status (TOS/TAS) on the other hand, in both patients with palmoplantar warts (n = 24) and healthy subjects as controls (n = 28). Results: Compared to the control group, our results showed that patients with warts had lower levels of sRAGE (1036.50 ± 207.60 pg/mL vs. 1215.32 ± 266.12 pg/mL, p < 0.05), higher serum levels of TOS (3.17 ± 0.27 vs. 2.93 ± 0.22 µmol H2O2 Eq/L, p < 0.01), lower serum levels of TAS (1.85 ± 0.12 vs. 2.03 ± 0.14 µmol Trolox Eq/L, p < 0.01) and minor variations of the inflammation parameters (high sensitivity-CRP, interleukin-6, fibrinogen, and erythrocyte sedimentation rate). Moreover, in patients with warts, sRAGE positively correlated with TAS (r = 0.43, p < 0.05), negatively correlated with TOS (r = −0.90, p < 0.01), and there was no significant correlation with inflammation parameters. There were no significant differences regarding the studied parameters between groups when we stratified the patients according to the number of the lesions and disease duration. Conclusions: Our results suggest that sRAGE acts as a negative regulator of oxidative stress and could represent a mediator involved in the development of warts. However, we consider that the level of sRAGE cannot be used as a biomarker for the severity of warts. To the best of our knowledge, this is the first study to demonstrate that sRAGE could be involved in HPV pathogenesis and represent a marker of oxidative stress in patients with warts.


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