SUSCEPTIBILITY OF BRAINS FROM PATIENTS WITH ALZHEIMERS-DISEASE TO OXYGEN-STIMULATED LIPID-PEROXIDATION AND DIFFERENTIAL SCANNING CALORIMETRY

The formation of thiobarbituric-acid-reactive substances (TBARS) indicative of oxygen-induced lipid peroxidation in vitro was assayed in the frontal cortex, hippocampus, putamen, basal nucleus of Meynert and substantia nigra from controls and patients with Alzheimer's disease. A significant increase of oxygen-stimulated formation of TBARS in vitro was found in the frontal cortex and substantia nigra of Alzheimer's-type brains, while there was only a trend to an increase in the basal nucleus of Meynert. In addition, induction of lipid peroxidation in vitro by incubation with a Fenton reagent did not result in significant differences between control and pathological brain areas. Levels of total iron in the brains from patients with Alzheimer's disease and controls did not differ significantly with respect to the same brain region investigated. Further analysis of frontal cortex, substantia nigra and basal nucleus of Meynert using differential scanning calorimetry revealed significantly lower thermostability of these areas in Alzheimer's disease. Our data suggest that, within distinct brain regions, Alzheimer brains differ from normal brains with respect to their susceptibility to peroxidation in vitro and to their resistance to thermic stress. These results implicate changes in cell membrane constituents and cytoarchitecture.