Oxidative stress-inducing carbonyl compounds from common foods: novel mediators of cellular dysfunction.
BACKGROUND
The general increase in reactive oxygen species generated from glucose-derived advanced glycation endproducts (AGEs) is among the key mechanisms implicated in tissue injury due to diabetes. AGE-rich foods could exacerbate diabetic injury, at least by raising the endogenous AGE.


METHODS
Herein, we tested whether, prior to ingestion, diet-derived AGEs contain species with cell activating (TNFalpha), chemical (cross-linking) or cell oxidative properties, similar to native AGEs. Glutathione (GSH) and GSH peroxidase (GPx) were assessed after exposure of human umbilical vein endothelial cell (HUVECs) to affinity-purified food-AGE extracts, each exposed to 250 degrees C, for 10 min, along with synthetic AGEs.


RESULTS
Animal product-derived AGE, like synthetic methylglyoxal-bovine serum albumin (MG-BSA), AGE-BSA, and AGE-low density lipoprotein (AGE-LDL), induced a dose- and time-dependent depletion of GSH (()60-75%, p, 0.01) and an increase in GPx activity (()500-600%, p < 0.01), consistent with marked TNFalpha and cross-link formation (p < 0.05); this contrasted with the low bioreactivity of starch/vegetable AGE-extracts, which was similar to that of control BSA and CML- BSA and BSA (p:NS). Anti-AGE-R1,2,3 and -RAGE IgG each inhibited cell-associated (125) I-dAGE by approximately 30-55%; GSH/GPx were effectively blocked by N-acetyl-cysteine (NAC, 800 uM, p < 0.01) and aminoguanidine-HCl (AG, 100 uM, p < 0.01).


CONCLUSIONS
Thus, food-derived AGE, prior to absorption, contain potent carbonyl species, that can induce oxidative stress and promote inflammatory signals.
Cai
Weijing
W
Division of Experimental Diabetes and Aging, Department of Geriatrics, Mount Sinai School of Medicine, New York, NY 10029, USA.
Gao
Qiao-Di
QD
Zhu
Li
L
Peppa
Melpomeni
M
He
Cijiang
C
Vlassara
Helen
H
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D005502:Food / Q000009:adverse effects*; D005978:Glutathione / Q000032:analysis; D005979:Glutathione Peroxidase / Q000032:analysis; D017127:Glycation End Products, Advanced / Q000138:chemical synthesis / Q000494:pharmacology*; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D008077:Lipoproteins, LDL / Q000032:analysis; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology
D003432:Cross-Linking Reagents; D017127:Glycation End Products, Advanced; D006146:Guanidines; D008077:Lipoproteins, LDL; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D005979:Glutathione Peroxidase; D005978:Glutathione; C004479:pimagedine; D000111:Acetylcysteine