Mitochondria and Ageing

Aging is a complex and multifactorial process, characterized by a progressive decline of energy metabolism and physiological functions. Although considered a regular process occuring in all living organisms, aging is associated with accumulative oxidative damage of cellular biomolecules and with increased susceptibility to age-related diseases. Mitochondria are central organelles in energy metabolism by housing several metabolic pathways and producing the major part of ATP used in the cell, through the oxidative phosphorylation. During electron transport, mitochondria produce ROS constantly, being considered as the major source of these species. Further, mitochondria are involved in Ca2+ homeostasis and in the triggering and regulation of cell death. The impairment of all these mitochondrial functions seems to be involved in aging and aging-related diseases. Several theories have suggested that aging is a result of accumulated oxidative ROS-mediated damage and the modulation of mitochondrial ROS production observed in different situations, including circadian variations and caloric restriction, seems to play an important role in aging process. In this chapter, a general view of mitochondrial functions potentially implicated in extended lifespan and aging will be provided and mitochondrial dysfunctions associated with aging and diseases will be discussed.