The Swedish APP670/671 Alzheimer's disease mutation: the first evidence for strikingly increased oxidative injury in the temporal inferior cortex.
To evaluate the level of oxidative stress (OS) in familial Alzheimer's disease (FAD), we analysed four cerebrocortical areas from patients with Swedish FAD bearing the APP670/671 mutation. The temporal inferior cortex (TIC) from Swedish FAD patients revealed a striking 2- to 3-fold increase in diene conjugates, lipid peroxides and protein carbonyls, compared to sporadic Alzheimer's disease (AD). Compared with TIC from sporadic AD patients, the mutation carriers showed a markedly decreased activity of catalase (CAT) in the same area, and the same trend was found for another antioxidant enzyme, superoxide dismutase. These results are consistent with the deep oxidative injury of TIC in Swedish FAD. In the frontal inferior cortex (FIC), sensory postcentral cortex (SPCC) and occipital primary cortex (OPC) from Swedish FAD, the parameters of oxidative injury tended to be higher than in sporadic AD. Only the increase in the levels of lipid hydroperoxides in SPCC and of protein carbonyls in OPC was significant. Compared to sporadic AD, Swedish FAD showed a significant increase in GSSG levels and the GSSG/2GSH ratio in the FIC, SPCC and OPC. A significantly decreased activity of CAT was detectable for the SPCC and OPC in Swedish FAD. Increased OS might play a crucial role in the rapid progression of Swedish FAD from the associative temporal cortex to the primary cerebrocortical areas.