Modulation of cell death in age-related diseases.

Aging is a stage of life of all living organisms. According to the free-radical theory, aging cells gradually become unable to maintain cellular homeostasis due to the adverse effects of reactive oxygen species (ROS). ROS can cause irreversible DNA mutations, protein and lipid damage which are increasingly accumulated in the course of time if cells could not overcome these effects by the antioxidant defence system. Accrued damaged molecules in cells may either induce cellular death or contribute to develop various pathologies. Hence, programmed cell death mechanisms, apoptosis and autophagy, play a vital role in the aging process. Although they are strictly controlled by various interconnected signalling pathways, alterations in their regulations may contribute to severe pathologies including cancer, Alzheimer's and Parkinson's diseases. In this review, we summarized our current understanding and hypotheses regarding oxidative stress and age-related dysregulation of cell death signalling pathways.