Imbalances of trace elements related to oxidative damage in Alzheimer's disease brain.

Four elements that have been implicated in free-radical-induced oxidative stress in Alzheimer's disease (AD) were measured by instrumental neutron activation analysis (INAA) in seven brain regions from 58 AD patients and 21 control subjects. A statistically significant elevation of iron and zinc was observed in multiple regions of AD brain, compared with controls. Mercury was elevated in AD in most regions studied, but the high variability of mercury levels in both AD and control subjects prevented the AD-control difference from reaching significance. Selenium, a protective agent against mercury toxicity, was significantly elevated only in AD amygdala. The elevation of iron and zinc in AD brain has the potential of augmenting neuron degeneration through free radical processes.