Apoptosis: a modulator of cellular homeostasis and disease states.

In normal epithelial tissue, a homeostatic balance is maintained between cell replication and apoptosis. Disruption of this balance has serious pathological consequences in disease states, such as Sjögren's syndrome, salivary gland degeneration, and cancers. Apoptosis may be modulated by cytokine endogenous factors and exogenous factors. A vast array of environmental compounds, such as differentiating agents and microconstituents found in the diet, initiate apoptosis through a redox signal mechanism. In addition to increasing apoptosis, these redox signals and transient or permanent changes in cellular redox status elevate detoxification enzymes known to protect against many disease states. Clearly a further understanding of the regulation of apoptosis and protective enzyme elevation by exogenous redox signals will lead to the development of future therapeutic strategies against disease.