Influence of apolipoprotein E genotype on blood redox status of Alzheimer's disease patients

The blood redox status of probable Alzheimer's Disease (AD) patients and co ntrol subjects with distinct Apo E genotypes was investigated. It was asses sed by measuring the levels of hydroperoxides (MDA) in plasma and erythrocy tes, the levels of the antioxidant defense system (enzymatic and non-enzyma tic) in plasma, erythrocytes, platelets and leukocytes, the activities of c atechol-O-methyltransferase (COMT) in erythrocytes and monoamine oxidase-B (MAO-B) in platelets and also the activity of the mitochondrial respiratory chain in leukocytes. No significant differences were found between the Apo E genotype and MDA, uric acid, vitamin E and reduced-glutathione (GSH) lev els in plasma; MDA, vitamin E, GSH, superoxide-dismutase (SOD), glutathione -peroxidase (GSH-Px) and COMT levels in erythrocytes; vitamin E levels in t he platelets of AD patients and control subjects. However, the uric acid le vels in plasma and the COMT levels in erythrocytes of AD patients and contr ol subjects with the epsilon 4 allele were significantly lower than those o bserved in control subjects without the epsilon 4 allele. Moreover, the dur aquinol oxidation level in leukocytes of AD patients with the epsilon 4 all ele was significantly higher than that in AD patients without the epsilon 4 allele and control subjects with and without the epsilon 4 allele. The mea ning of these results is discussed in terms of involvement of oxidative str ess in the etiopathogenesis of AD.