Oxidative Stress in the Progression of Alzheimer Disease in the Frontal Cortex

• Published in: Journal of neuropathology and experimental neurology Vol. 69; no. 2; pp. 155 - 167
• Main Authors: Ansari, Mubeen A., Scheff, Stephen W.
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD American Association of Neuropathologists, Inc 01.02.2010; Lippincott Williams & Wilkins; Oxford University Press
• Subjects: Aged; Aged, 80 and over; Aldehydes - metabolism; Alzheimer Disease - metabolism; Alzheimer Disease - psychology; Antioxidants - metabolism; Biological and medical sciences; Biomarkers - metabolism; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Disease Progression; Female; Frontal Lobe - metabolism; Humans; Male; Medical sciences; Mental Status Schedule; Neurology; Oxidative Stress; Protein Carbonylation; Synapses - metabolism; Thiobarbituric Acid Reactive Substances - metabolism; Tissue Distribution; Tyrosine - analogs & derivatives; Tyrosine - metabolism; Oxidative stress; Nervous system diseases; Cognitive disorder; Free radicals; Alzheimer disease; Central nervous system; Frontal cortex; Free radical; Encephalon; Cerebral disorder; Mitochondria; Synapse; Neurodegeneration; Central nervous system disease; Degenerative disease; mild cognitive impairment; Synapses
• ISSN: 0022-3069; 1554-6578; 1554-6578
• DOI: 10.1097/NEN.0b013e3181cb5af4

We investigated oxidative stress in human postmortem frontal cortexfrom individuals characterized as mild cognitive impairment (n= 8), mild/moderate Alzheimer disease (n = 4), and late-stage Alzheimer disease (n = 9). Samples from subjects with no cognitive impairment (n = 10) that were age- and postmortem interval-matched with these cases were used as controls. The short postmortem intervalbrain samples were processed for postmitochondrial supernatant, nonsynaptic mitochondria, and synaptosome fractions. Samples were analyzed for several antioxidants (glutathione, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, glucose-6-phosphate dehydrogenase, superoxide dismutase, catalase) and the oxidative marker, thiobarbituric acid reactive substances. The tissue was also analyzed for possible changes in protein damage using neurochemical markers for protein carbonyls, 3-nitrotyrosine, 4-hydroxynonenal, andacrolein. All 3 neuropil fractions (postmitochondrial supernatant, mitochondrial, and synaptosomal) demonstrated significant disease-dependent increases in oxidative markers. The highest changes were observed in the synaptosomal fraction. Both mitochondrial and synaptosomal fractions had significant declines in antioxidants (glutathione, glutathione peroxidase, glutathione-S-transferase, and superoxide dismutase). Levels of oxidative markers significantly correlated with Mini-Mental Status Examination scores. Oxidative stress was more localized to the synapses, with levels increasing in a disease-dependent fashion. These correlations implicate an involvement of oxidative stress in Alzheimer disease-related synaptic loss.