The involvement of cell cycle events in the pathogenesis of Alzheimer's disease

Most neurons undergo their last cell division within the first 1 to 2% of the lifespan of an organism. This has been interpreted to mean that adult neurons are permanently postmitotic, but Alzheimer's disease (AD) is an example of a late-onset neurodegenerative disease that challenges this concept. In AD, neurons in populations at risk for death reactivate their cell cycle and replicate their genome - but rather than complete the cycle with mitosis and cytokinesis, the neurons die. While opening new perspectives on the etiology of AD dementia, the simple linear model suggested by this description gains in complexity with the maturation of the adult brain. This complexity makes the full understanding of the relationship between cell division and cell death more difficult to achieve. The quest for understanding is worthwhile, however, as fresh avenues for therapeutic intervention are the prizes for success.