Aneuploidy in Lewy body diseases.

An increase in DNA content is associated with neuronal degeneration in Alzheimer's disease but has not been evaluated in Lewy body diseases. Using stereological principles, flow cytometry, and standard histopathologic methods, we evaluated the number and DNA content of neurons and all cells and the severity of Lewy and Alzheimer pathologies, in brain regions affected at different stages in Lewy body diseases compared with controls. An increase in neuronal DNA content was observed in all the affected brain regions examined, although this change was related to different pathologies. In the substantia nigra, increased neuronal DNA content related to neuronal loss, whereas in the cortex and hippocampus, increased neuronal DNA content related to Alzheimer pathologies. Of note, increased neuronal DNA content did not relate to the deposition of Lewy bodies in any region examined. These data support the concept that increased DNA content increases neuronal susceptibility to degeneration and Alzheimer pathologies.