Sequestering Agents of Intermediate Reactive Aldehydes as Inhibitors of Advanced Lipoxidation End-Products (ALEs)

2006 ◽  
pp. 877-929 ◽  
Author(s):  
Marina Carini ◽  
Giancarlo Aldini ◽  
Roberto Maffei Facino
Keyword(s):  
Reactive Aldehydes ◽  
End Products

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.

Low plasma carnosinase activity promotes carnosinemia after carnosine ingestion in humans

2012 ◽  
Vol 302 (12) ◽  
pp. F1537-F1544 ◽  
Author(s):  
Inge Everaert ◽  
Youri Taes ◽  
Emile De Heer ◽  
Hans Baelde ◽  
Ana Zutinic ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Protein Content ◽  
Healthy Subjects ◽  
Plasma Samples ◽  
Advanced Glycation ◽  
Highly Active ◽  
Reactive Aldehydes ◽  
Glycation End Products ◽  
End Products ◽  
Reduced Risk

A polymorphism in the carnosine dipeptidase-1 gene ( CNDP1), resulting in decreased plasma carnosinase activity, is associated with a reduced risk for diabetic nephropathy. Because carnosine, a natural scavenger/suppressor of ROS, advanced glycation end products, and reactive aldehydes, is readily degraded in blood by the highly active carnosinase enzyme, it has been postulated that low serum carnosinase activity might be advantageous to reduce diabetic complications. The aim of this study was to examine whether low carnosinase activity promotes circulating carnosine levels after carnosine supplementation in humans. Blood and urine were sampled in 25 healthy subjects after acute supplementation with 60 mg/kg body wt carnosine. Precooled EDTA-containing tubes were used for blood withdrawal, and plasma samples were immediately deproteinized and analyzed for carnosine and β-alanine by HPLC. CNDP1 genotype, baseline plasma carnosinase activity, and protein content were assessed. Upon carnosine ingestion, 8 of the 25 subjects (responders) displayed a measurable increase in plasma carnosine up to 1 h after supplementation. Subjects with no measurable increment in plasma carnosine (nonresponders) had ∼2-fold higher plasma carnosinase protein content and ∼1.5-fold higher activity compared with responders. Urinary carnosine recovery was 2.6-fold higher in responders versus nonresponders and was negatively dependent on both the activity and protein content of the plasma carnosinase enzyme. In conclusion, low plasma carnosinase activity promotes the presence of circulating carnosine upon an oral challenge. These data may further clarify the link among CNDP1 genotype, carnosinase, and diabetic nephropathy.

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