Hyperglycemia and Oxidative Stress in the Human Brain With Diabetes

The purpose of this study is to use an MRI exam to measure the concentrations of glutathione (GSH) and Vitamin C (Asc) in the brains of normal healthy persons and type 2 diabetic persons. The study will look at the relationship between chronic hyperglycemia and the levels of these naturally occurring chemicals in the brain.

Cerebral GSH and Asc concentrations are modulated by increased oxidative stress induced by hyperglycemia in diabetes and reflect changes in the cerebral antioxidant defense system. Inhibition of cellular uptake of Asc by hyperglycemia further hampers maintaining adequate antioxidant capacities. Reduced concentrations of these antioxidants might serve as good indicators of increased susceptibility to oxidative damage, impaired cellular uptake or the antioxidant, and further, as sensitive in vivo biomarkers to assess early manifestations or progression of diabetic complications and the efficacy of the antioxidant therapy in the human brain. Specific aims (1) to determine cerebral concentrations of GSH and Asc in the living brain of healthy controls and type 2 diabetic patients; (2) to quantify the effect of chronic hyperglycemia on cellular uptake of Asc across the blood-brain barrier.

Inclusion Criteria: Good health except for having type 2 diabetes Being treated with diet, insulin, or oral hyperglycemic agents Male or non pregnant female Non-smoker HbA1c 8 or above Able to provide informed consent Exclusion Criteria: Presence of mental illness Co-existing chronic inflammatory condition or neurological disease or diseases associated with abnormal glutathione metabolism BMI over 35 Smoker