Apoptosis: mechanisms and clinical implications

The balance between cell survival and death is under tight genetic control. A multiplicity of extracellular signals and intracellular mediators is inv olved in maintaining this balance. When the cell is exposed to physical, bi ochemical or biological injury, or deprived of necessary substances, it act ivates a series of stress-response genes. With minimal insults, the cell ma y recover. With greater insults, single cell death, or apoptosis, results; the cell dies and is recycled to its neighbours. If the insult overwhelms a large number of cells then necrosis ensues, with an accompanying inflammat ory response. Dysregulation of the controlling mechanisms of this system re sults in disease. Deficient apoptosis is associated with cancer, auto-immun ity and viral infections. Excessive apoptosis is associated with ischaemic heart disease, stroke, neurodegenerative disease, sepsis and multiple organ dysfunction syndrome. There are myriad therapeutic options unfolding as un derstanding is gained of apoptosis and its control.