Increased glutathione peroxidase activity in erythrocytes in patients with Alzheimer's disease/senile dementia of Alzheimer's type

Abstract
Glutathione peroxidase (GSH-Px) activity in erythrocytes was studied in 9 patients with Alzheimer''s disease/senile dementia of Alzheimer''s type (AD/SDAT) of ages 34-64 years and compared with that in 16 healthy controls of ages 21-66 years. The median GSH-Px activity in erythrocytes from AD/SDAT patients was 408, .mu.kat/1 (range 338-500 .mu.kat/1) and that from healthy controls 348, .mu.kat/1 (range 258-439 .mu.kat). This difference was significant (p < 0.005) Wilcoxon rank test. Since there are great clinical and pathological similarities between AD/SDAT and the dementia of Down''s syndrome (DS) patients and since both these groups of patients have increased activity of the selenium-dependent enzyme GSH-Px, it is suggested that there could be a similar metabolic background of the dementia. Many findings in the oxidative metabolism of DS suggest increased oxidative damage with an elevation of the turnover of superoxides to peroxides within cells and with a secondary biochemical modification such as increase in tissual GSH-Px activity. A similar mechanism with elevation peroxidation within cells might be responsible for the present finding of increased GSH-Px activity in erythrocytes and for the development of dementia in AD/SDAT.