Lipid Peroxidation and Nitrite Plus Nitrate Levels in Brain Tissue from Patients with Alzheimer's Disease

Background: Although oxidative stress has been implicated in the pathogenesis of neurodegenerative diseases, data found in the literature are still a matter of controversy.

Objective: To study lipid peroxidation and nitrite plus nitrate levels in brain specimens (frontal, parietal, temporal, and occipital cortices) from 8 patients with Alzheimer's disease (AD) in comparison to 6 young and 7 age-matched controls.

Methods: Lipid peroxidation was estimated by the thiobarbiturate test for malonaldehyde and nitrate/nitrite using the Griess method.

Results: Our results show a clear malonaldehyde increase tendency in all brain areas from AD cases in relation to older individuals and younger controls. In temporal cortex there was no difference between AD cases and age-matched controls. We suggest that this may be due to incipient temporal cortex damage in control individuals and that this area could be more susceptible to age-related changes. We showed that nitrite plus nitrate levels significantly decrease in brain areas of AD cases in relation to young controls. Except for the frontal cortex, there was a trend for a decreased concentration of nitrite/nitrate in the aged group in all brain areas studied as compared with young controls.

Conclusion: Our results support a major role for lipid peroxidation alterations in cerebral cortex of AD patients and showed not only a decrease in nitrite/nitrate levels in frontal cortex of AD cases in relation to young and old individuals, but also a reduction in these nitric oxide metabolites in the other cortical areas as related to young controls.