scholarly journals Non-enzymatic glycation of proteins: from diabetes to cancer

2010 ◽  
Vol 56 (2) ◽  
pp. 168-178 ◽  
Author(s):  
N.A. Ansari ◽  
Z. Rasheed

Incubation of proteins with glucose leads to their non-enzymatic glycation and formation of Amadori products known as an early glycation product. Oxidative cleavage of Amadori products is considered as a major route to advanced glycation endproducts (AGEs) formation in vivo. Nonenzymatic glycation of proteins or Maillard reaction is increased in diabetes mellitus due to hyperglycemia and leads to several complications such as blindness, heart disease, nerve damage and kidney failure. Accumulation of the early and advanced glycation products in plasma and tissues of diabetic patients and causes production of autoantibodies against corresponding products. The advanced glycation products are also associated with other diseases like cancer. This review summarizes current knowledge of these stage specific glycated products as common and early diagnostic biomarkers for the associated diseases and the complications with the aim of a novel therapeutic target for the diseases.

Author(s):  
Annayara C. F. Fernandes ◽  
Jeane B. Melo ◽  
Vanize M. Genova ◽  
Ádina L. Santana ◽  
Gabriela Macedo

Background: Glycation is a chemical reaction that synthesize advanced glycation endproducts (AGEs). The AGEs irreversibly damage macromolecules present in tissues and organs, leading to the impairment of biological functions. For instance, the accumulation of AGEs induces oxidative stress and consequently inflammatory responses in human body, leading to the on set/worsening of diseases, including obesity, asthma, cognitive impairment, and cancer. There is a current demand on natural and low-cost sources of antiglycant agents. As a result, food phytochemicals presented promising results to inhibit glycation and consequently, the formation of AGEs. Objective: Here, we describe the mechanism of glycation on the worsening of diseases, the methods os detection, and the current findings on the use of phytochemicals (phenolic compounds, phytosterols, carotenoids, terpenes and vitamins) as natural therapeuticals to inhibit health damages via inhibition of AGEs in vitro and in vivo. Methods: This manuscript reviewed publications available in the PubMed and Science Direct databases dated from the last 20 years on the uses of phytochemicals to inhibit the AGEs in vitro and in vivo. Also, recent patents on the use of anti-glycant drugs were reviewed using the Google Advanced Patents database. Results and Discussion: Phenolic compounds have been mostly studied to inhibit AGEs. Food phytochemicals derived from agroindustry wastes, including peanut skins, and the bagasses derived from citrus and grapes are promising antiglycant agents via scavenging of free radicals, metal ions, the suppression of metabolic pathways that induces inflammation, the activation of pathways that promote antioxidant defense, the blocking of AGE connection with the receptor for advanced glycation endproducts (RAGE). Conclusion: Phytochemicals derived from agroindustry are promising anti-glycants, which can be included to replace synthetic drugs for AGE inhibition, and consequently to act as a therapeutical strategy to prevent and treat diseases caused by AGEs, including diabetes, ovarian cancer, osteoporosis, and Alzheimer’s disease.


2019 ◽  
Vol 160 (40) ◽  
pp. 1567-1573 ◽  
Author(s):  
Kinga Makk-Merczel ◽  
András Szarka

Abstract: The relationship between the potentially developing complications of the 451 million people affected by diabetes and hyperglycaemia can be based on the enhanced generation of advanced glycation endproducts and the more intensive oxidative and carbonyl stress. Advanced glycation endproducts generated partly due to carbonyl stress play an important role in the pathogenesis of diabetic complications such as elevated arterial thickness, vascular permeability, enhanced angiogenesis or the more rigid vessels induced nephropathy, neuropathy, retinopathy. Furthermore, the elevated thrombocyte aggregation, the reduced fibrinolysis induced elevated coagulation, and the atherosclerosis or the mitochondrial dysfunction are important as well. The most potent target of both the non-oxidative and oxidative generation of advanced glycation endproducts can be the scavenging of α,β-unsaturated aldehydes. Although, aminoguanidine, the prototype of scavenger molecules, showed protection in different animal models, it failed in the human clinical studies. Finally, the clinical studies were terminated almost 20 years ago. The endogen dipeptide L-carnosine was also expected to mitigate the complications due to carbonyl stress. However, its clinical significance was limited by the serum carnosinases and by the consequent low serum stability and bioavailability. The carnosinase resistance of the molecule can be achieved by the change of the carboxyl group of the molecule to hydroxyl group. At the same time, the biosafety and the carbonyl stress scavenging activity of the molecule could be preserved. Although clinical studies could not be performed in the last six months, on the basis of the in vitro and in vivo results, carnosinole seems to be a promising compound to mitigate and prevent the diabetic complications. Thus it is worth to the attention of the clinicians. Orv Hetil. 2019; 160(40): 1567–1573.


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