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 less than 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 elevated 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.

Blood Activity of Cu/Zn Superoxide Dismutase, Glutathione Peroxidase and Catalase in Alzheimer’s Disease: A Case-Control Study

“…This result may be explained by the fact that cellular and extracellular media contain different isoenzymes [21,22] or by the high variability of plasma composition. The results we obtained on erythrocytes are partly consistent with the data of Anneren et al [23] who found an increased activity of GPx in erythrocytes of 9 senile DAT/DAT patients in comparison to 16 healthy con trols. Conversely, Sulkawa et al [10] ob served no change in erythrocyte GPx and SOD in patients with Alzheimer's disease as compared with 5 controls, but these authors examined small series of patients.…”

Lipid Peroxidation and Free Radical Scavengers in Alzheimer’s Disease

“…There is a significative decrease of GSH-Px in the patient group contrary to the study of Anneren et al [31] which concerned younger individuals. Like Burns and Holland [16], we observed a significant decrease of free and total vitamin E in serum (p < 0.03) in the patient group.…”

Decreased plasma antioxidants in patients with Alzheimer's disease

“…Moreover, it is well known that unconjugated bilirubin is the main form of the bile pigment endowed with antioxidant activity . Many other previous studies about the neurological disorders provide evidence for peripheral (plasma and RBC)-central relations of the indices of abnormal free radical metabolism and relations between peripheral measures of antioxidant defense system and CNS findings (Anneren et al, 1986;Zemlan et al, 1989;Subbarao et al, 1990;Reddy and Yao, 1996;Yao et al, 2000). The plasma unconjugated bilirubin levels are reflected in the plasma concentrations of total bilirubin.…”