Peripheral levels of glutathione and protein oxidation as markers in the development of Alzheimer's disease from Mild Cognitive Impairment.

There is a great interest in the relationship between Mild Cognitive Impairment (MCI) and the progression to Alzheimer's disease (AD). Several studies show the importance of oxidative stress in the pathogenesis of AD. The purpose of this study was the link between oxidative damage, MCI and AD. It analysed protein carbonyls and erythrocyte glutathione system plasma levels of 34 subjects with MCI, 45 subjects with AD and 28 age-matched control subjects. The results showed an increase in protein modification, a decrease in GSH levels and GSH/GSSG ratio in AD and MCI patients compared to age-matched control subjects (p<0.05). The present study shows that some peripheral markers of oxidative stress appear in MCI with a similar pattern to that observed in AD, which suggests that oxidative stress might represent a signal of the AD pathology. AD and MCI are biochemically equivalent. MCI does not necessarily need to progress to AD on a biochemical level.