I often occassionally encounter discussions of longevity and one question that invariably arises is "why do cells die?".
Well besides cell death from some abnormal or traumatic situation, cell death can be natural and the process is "apoptosis".
Apoptosis is a process of suicide by a cell in a multicellular organism. It is one of the main types of programmed cell death (PCD), and involves an orchestrated series of biochemical events leading to a characteristic cell morphology and death. The apoptotic process is executed in such a way as to safely dispose of cellular debris.
In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis is carried out in an orderly process that generally confers advantages during an organism's life cycle. For example, the differentiation of fingers and toes in a developing human embryo requires cells between the fingers to initiate apoptosis so that the digits can separate. Between 50 billion and 70 billion cells die each day due to apoptosis in the average human adult. For an average child between the ages of 8 to 14, approximately 20 billion to 30 billion cells die a day. In a year, this amounts to the proliferation and subsequent destruction of a mass of cells equal to an individual's body weight.
Research on apoptosis has increased substantially since the early 1990s. In addition to its importance as a biological phenomenon, defective apoptotic processes have been implicated in an extensive variety of diseases. Excessive apoptosis causes hypotrophy, such as in ischemic damage, whereas an insufficient amount results in uncontrolled cell proliferation, such as cancer.
http://en.wikipedia.org/wiki/ApoptosisFascinating. The extension of aging would require the reduction in rate of apoptosis from that in an adult to that of a child - or so it would seem. But that would seemingly have to be balanced against the potential for cancer.
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