INCREASED AMOUNT OF ZINC IN THE HIPPOCAMPUS AND AMYGDALA OF ALZHEIMERS-DISEASED BRAINS - A PROTON-INDUCED X-RAY-EMISSION SPECTROSCOPIC ANALYSIS OF CRYOSTAT SECTIONS FROM AUTOPSY MATERIAL

Zinc has been implicated as a contributing cause of the neuropathology of Alzheimer's disease (AD), but consensus on the zinc content of AD brains has not yet been established. In the present study, multi-eleme nt PIXE was used to measure zinc in cryostat sections of brain tissue from AD patients and from normal control subjects. Compared to their a ge-matched controls, the AD patients showed an increase in zinc in the hippocampal and amygdalar regions. The instrumental PIXE assays do no t show whether the zinc changes are due to altered zinc in the boutons of Zinc-ENriched (ZEN) neurons, i.e., zinc ions in synaptic vesicles, or to changes in the amount of zinc tightly bound to macromolecules. We hypothesise that the increased zinc level is caused by an increase in the amount of ZEN terminals. Such an increase could be the result o f a sprout of ZEN terminals in diseased areas of the brain. (C) 1997 E lsevier Science B.V.