Autolysosomes in Alzheimer's disease and their possible role in its pathogenesis. An ultrastructural study

In 10 cases of senile dementia of Alzheimer's type (AD) a systematic post-mortem ultrastructural analysis was performed. Attention was paid mainly to the presence of autolysosomes in the neuropil of the brain cortex. Autolysosomes appeared as osmiophilic dense bodies (DB) which originated in synaptic terminals and peripheral nerve-cell processes. DBs contained sequestrated cellular material wrapped by pinched off, invaginated cell membrane. DB were very frequent also in fields where no senile plaques (SP) and/or nerve-cell processes with paired helical filaments (PHF) were present. Abnormal fermentative degradation of DBs and their possible negative influence on the plasmatic flow in nerve-cell processes is discussed.