Increased markers of oxidative stress in patients with Alzheimer's disease

The exact cause of the pathogenesis of Alzheimer's disease (AD) is unknown. There is a growing body of evidence that oxidative stress may play a signi ficant role in the slow and progressive neurodegeneration that is the hallm ark of this disorder. We carried out a case-control study comparing periphe ral blood markers of oxidative stress in a group of Alzheimer patients and elderly healthy control subjects. We measured plasma levels of reduced glut athione (GSH), oxidized glutathione (GSSG) and the peroxidation product mal ondialdehyde (MDA). Baseline measurements showed that individuals with AD h ave significantly higher levels of GSSG and MDA compared to controls (p= 0. 002, 0.0003 respectively). There was no significant difference in GSH level s between the two groups. Using the Single Cell Gel Electrophoresis assay ( the 'comet' assay), we also determined the DNA single strand breaks in fres hly isolated lymphocytes. A statistically significant increase in mean basa l DNA strand breaks was observed in AD subjects compared with elderly contr ol subjects (p= 0.0001). In summary, the data presented in this work sugges t that individuals with AD may be subject to increased oxidative stress and disturbed defence mechanisms. This is in broad agreement with findings fro m studies carried out in AD brain tissue, and in support of the hypothesis that oxidative stress may have an aetiological role in AD pathogenesis.