Neurochemical changes in white matter. Aged human brain and Alzheimer's disease.

We report a reduction in isolatable myelin in white matter from regional areas of aged human brain. This decrease was most prominent in association subcortex of Alzheimer's material. We also found structural changes in myelin lipids. These changes involved an increase in unsaturated acyl chains and suggest an age-related instability of subcortical white matter. This specific chemical change in myelin glycosphingolipids has been found in all regional areas of normal aged and Alzheimer's brain material. This remains an age-related molecular change that seems unrelated to the pathophysiology of senile dementia of the Alzheimer's type.