F4 ‐ Isoprostanes as Specific Marker of Docosahexaenoic Acid Peroxidation in Alzheimer's Disease

: F2‐isoprostanes are prostaglandin‐like compounds derived from free radical‐catalysed peroxidation of arachidonic acid. Peroxidation of eicosapentaenoic acid produces F3‐isoprostanes, whereas peroxidation of docosahexaenoic acid would give F4‐isoprostanes. This study demonstrates the presence of esterified F4‐isoprostanes in human brain and shows that levels are elevated in certain brain cortex regions in Alzheimer's disease. Our data with Alzheimer's disease suggest that analysis of F4‐isoprostanes will provide new opportunities to study lipid peroxidation in the neurodegenerative diseases.