Acute exposure to low glucose rapidly induces endothelial dysfunction and mitochondrial oxidative stress: role for AMP kinase. Arterioscler Thromb Vasc Biol 2012 Mar;32(3):712-20
Date
12/31/2011Pubmed ID
22207730Pubmed Central ID
PMC3319449DOI
10.1161/ATVBAHA.111.227389Scopus ID
2-s2.0-84857657883 (requires institutional sign-in at Scopus site) 110 CitationsAbstract
OBJECTIVE: Hypoglycemia is associated with increased mortality. The reasons for this remain unclear, and the effects of low glucose exposure on vascular endothelial function remain largely unknown. We endeavored to determine the effects of low glucose on endothelial cells and intact human arterioles.
METHODS AND RESULTS: We exposed human umbilical vein endothelial cells to low glucose conditions in a clinically relevant range (40-70 mg/dL) and found rapid and marked reductions in nitric oxide (NO) bioavailability (P<0.001). This was associated with concomitantly increased mitochondrial superoxide production (P<0.001) and NO-dependent mitochondrial hyperpolarization (P<0.001). Reduced NO bioavailability was rapid and attributable to reduced endothelial nitric oxide synthase activity and destruction of NO. Low glucose rapidly activated AMP kinase, but physiological activation failed to restore NO bioavailability. Pharmacological AMP kinase activation led to phosphorylation of endothelial nitric oxide synthase's Ser633 activation site, reversing the adverse effects of low glucose. This protective effect was prevented by L-NG-Nitroarginine methyl ester. Intact human arterioles exposed to low glucose demonstrated marked endothelial dysfunction, which was prevented by either metformin or TEMPOL.
CONCLUSION: Our data suggest that moderate low glucose exposure rapidly impairs NO bioavailability and endothelial function in the human endothelium and that pharmacological AMP kinase activation inhibit this effect in an NO-dependent manner.
Author List
Wang J, Alexanian A, Ying R, Kizhakekuttu TJ, Dharmashankar K, Vasquez-Vivar J, Gutterman DD, Widlansky MEAuthor
Michael E. Widlansky MD Center Director, Professor in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AMP-Activated Protein KinasesAdipose Tissue
Antioxidants
Arterioles
Cells, Cultured
Endothelium, Vascular
Enzyme Activation
Enzyme Activators
Enzyme Inhibitors
Glucose
Human Umbilical Vein Endothelial Cells
Humans
Hypoglycemia
Hypoglycemic Agents
Membrane Potential, Mitochondrial
Mitochondria
Nitric Oxide
Nitric Oxide Synthase Type III
Oxidative Stress
Phosphorylation
Serine
Signal Transduction
Superoxides
Time Factors
