Glutathione in Mild Cognitive Impairment

Subjects with MCI will be recruited by written informed consent using forms approved by the Baylor IRB. Subjects will stop nonvitamin supplements for 4wks before screening labs (blood count, HbA1c, glucose, lipid profile, liver profile, blood urea nitrogen, Creatinine, thyroid stimulating hormone, free T4), and for the entire 24wks duration of the study. 60 fasted subjects will have the following measures before and after 12wks of supplementation with cysteine (as N-acetylcysteine) plus glycine vs alanine: (1) Cognitive function using ADCS-PACC (Alzheimer's Disease Co-operative Study-Preclinical Alzheimer's Cognitive Composite which includes Free and Cued Selective Reminding Test, Immediate and Delayed paragraph recall score, Digit-Symbol Substitution Test, Mini mental state examination; (2) Red-cell concentrations of GSH, cysteine, glycine, glutamic acid; plasma malondialdehyde, F2/F3-isoprostanes, sICAM, sVCAM, E-selectin; endothelial function; (3) Mitochondrial glucose oxidation by calorimetry. Measures will be repeated for washout effects 12-wks after stopping supplements.

Inclusion Criteria at study entry: (1) Diagnosis of Mild Cognitive Impairment Exclusion Criteria at study entry: (1) hospitalization within past 3 months; (2) known diabetes; (3) creatinine greater than or equal to 1.5 mg/dL; (4) hemoglobin concentration less than 11 g/dL; (5) known liver disease, or AST/ALT greater than or equal to 2x ULN; (6) history of stroke, brain tumor, or active heart failure; (7) history of psychiatric disorders; (8) untreated depression.