TY - JOUR
T1 - High glucose increases nitric oxide synthase expression and superoxide anion generation in human aortic endothelial cells
AU - Cosentino, Francesco
AU - Hishikawa, Keiichi
AU - Katusic, Zvonimir S.
AU - Lüscher, Thomas F.
PY - 1997/7/1
Y1 - 1997/7/1
N2 - Background: Hyperglycemia is a primary cause of premature vascular disease. Endothelial cell dysfunction characterized by diminished endothelium-dependent relaxations is likely to be involved. Little is known about the molecular mechanisms of hyperglycemia-induced endothelial dysfunction. Methods and Results: This study was designed to determine the effect of hyperglycemia on the L-arginine/nitric oxide (NO) pathway. Expression of endothelial nitric oxide synthase (eNOS) mRNA and production of NO were studied in human aortic endothelial cells exposed to control levels (5.5 mmol/L) and high levels (22.2 mmol/L) of glucose for 5 days. We examined the effect of glucose on NO release by measuring changes in nitrite (NO2-) levels by Griess reaction. Superoxide anion (O2-) production was also examined by the ferrocytochrome c assay. NOS mRNA and protein expression, which were evaluated by reverse transcription-polymerase chain reaction and Western blotting, were approximately twofold greater in endothelial cells exposed to high glucose. Elevated glucose levels increased NO2 production by only 40% but increased the release of O2- by more than threefold. Conclusions: The present study demonstrates that prolonged exposure to high glucose increases eNOS gene expression, protein expression, and NO release. However, upregulation of eNOS and NO release is associated with a marked concomitant increase of O2- production. These results provide the molecular basis for understanding how chronic exposure to elevated glucose leads to an imbalance between NO and O2- . This may explain impaired endothelial function and be important for diabetic vascular disease.
AB - Background: Hyperglycemia is a primary cause of premature vascular disease. Endothelial cell dysfunction characterized by diminished endothelium-dependent relaxations is likely to be involved. Little is known about the molecular mechanisms of hyperglycemia-induced endothelial dysfunction. Methods and Results: This study was designed to determine the effect of hyperglycemia on the L-arginine/nitric oxide (NO) pathway. Expression of endothelial nitric oxide synthase (eNOS) mRNA and production of NO were studied in human aortic endothelial cells exposed to control levels (5.5 mmol/L) and high levels (22.2 mmol/L) of glucose for 5 days. We examined the effect of glucose on NO release by measuring changes in nitrite (NO2-) levels by Griess reaction. Superoxide anion (O2-) production was also examined by the ferrocytochrome c assay. NOS mRNA and protein expression, which were evaluated by reverse transcription-polymerase chain reaction and Western blotting, were approximately twofold greater in endothelial cells exposed to high glucose. Elevated glucose levels increased NO2 production by only 40% but increased the release of O2- by more than threefold. Conclusions: The present study demonstrates that prolonged exposure to high glucose increases eNOS gene expression, protein expression, and NO release. However, upregulation of eNOS and NO release is associated with a marked concomitant increase of O2- production. These results provide the molecular basis for understanding how chronic exposure to elevated glucose leads to an imbalance between NO and O2- . This may explain impaired endothelial function and be important for diabetic vascular disease.
KW - Diabetes mellitus
KW - Endothelium-derived factors
KW - Free radicals
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U2 - 10.1161/01.CIR.96.1.25
DO - 10.1161/01.CIR.96.1.25
M3 - Article
C2 - 9236411
AN - SCOPUS:0030837996
SN - 0009-7322
VL - 96
SP - 25
EP - 28
JO - Circulation
JF - Circulation
IS - 1
ER -