The role of apoptotic volume decrease and ionic homeostasis in the activation and repression of apoptosis

The mechanism of activation and repression of apoptosis has been a central focus of many studies examining the role of programmed cell death in both normal and pathological conditions. Despite intensive research efforts, the precise cellular and molecular mechanisms that trigger and/or prevent apoptosis remain undefined. A universal characteristic of apoptosis is the loss of cell volume or cell shrinkage, recently termed apoptotic volume decrease. While cell shrinkage has traditionally been viewed as a passive event during apoptosis, recent work from several laboratories has shown that the loss of cell volume, or more specifically the flux of ions associated with the change in cell size, play a critical role in the regulation of the cell death machinery. On going studies continue to support the hypothesis that the change in intracellular ions can alter a cells decision to die by apoptosis.