Jeong-Ho Oak

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Angiotensin II (Ang II) levels are increased in patients with diabetes, but mechanisms underlying its contribution to diabetic vascular diseases are incompletely understood. We recently reported that in aortic endothelial cells, Ang II induces endothelial nitric oxide synthase (eNOS) uncoupling to produce superoxide (O(2)*(-)) rather than nitric oxide(More)
This study for the first time confirmed the peroxidative role of the Amadori product derived from the glycation of phosphatidylethanolamine (PE), namely Amadori-PE. The product was synthesized from the reaction of dioleoyl PE with D-glucose, and then purified by a solid-phase extraction procedure, which was a key step in the next HPLC technique for the(More)
Peroxidized phospholipid-mediated cytotoxicity is involved in the pathophysiology of diseases [i.e., an abnormal increase of phosphatidylcholine hydroperoxide (PCOOH) in plasma of type 2 diabetic patients]. The PCOOH accumulation may relate to Amadori-glycated phosphatidylethanolamine (Amadori-PE; deoxy-D-fructosyl phosphatidylethanolamine), because(More)
BACKGROUND Dysfunctionally uncoupled endothelial nitric oxide synthase (eNOS) is involved in producing reactive oxygen species (ROS) in the diabetic endothelium. The present study investigated whether anti-diabetes drug Aminoguanidine (AG) has any effect on eNOS function and vascular oxidant stress. METHODS AND RESULTS Blood glucose levels were increased(More)
Glycation has been implicated in the endothelial dysfunction that contributes to both diabetes- and aging-associated vascular complications. The aim of the present study was to determine whether Amadori-glycated phosphatidylethanolamine (Amadori-PE), a lipid-linked glycation compound that is formed at an increased rate in hyperglycemic states, affected(More)
Maillard reactions are among the most important of the chemical and oxidative changes occurring in food and biological samples that contribute to food deterioration and to the pathophysiology of human disease. Although the association of lipid glycation with this process has recently been shown, the number of lipid glycation products in food and biological(More)
The endothelial nitric oxide synthase (eNOS) requires tetrahydrobiopterin (H(4)B) as a cofactor and, in its absence, produces superoxide (O(2)(·-)) rather than nitric oxide (NO(·)), a condition referred to as eNOS uncoupling. DOCA-salt-induced hypertension is associated with H(4)B oxidation and uncoupling of eNOS. The present study investigated whether(More)
Glycation has been thought to participate in diabetic vascular diseases. However, there are no reports about the effects of lipid glycation on endothelial dysfunction. In this study, we have evaluated whether Amadori-glycated phosphatidylethanolamine (Amadori-PE), a lipid-linked glycation compound, affected proliferation, migration, and tube formation of(More)
Amadori-glycated phosphatidylethanolamine (Amadori-PE), a nonenzymatically glycated lipid formed under hyperglycemic conditions, is known as a reliable indicator of lipid glycation in vivo. We have quantified the Amadori-PE concentration in human plasma samples using a reverse-phase liquid chromatography-tandem mass spectrometry with neutral loss scan or(More)
This study describes the occurrence of 3-hydroxy-5-hydroperoxy-2-methyl-5,6-dihydropyran-4-one (HMDP) in plasma obtained from normal subjects and patients with type 2 diabetes. We have shown previously that HMDP is a novel hydrophilic hydroperoxide formed in the in vitro Maillard reaction that could be analyzed using ultrasensitive chemiluminescence(More)