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Most of the cells within the human body have defined life spans. Most cells
can only divide and thus replace themselves between 30 and 50 times. After
a cell has undergone its 50 divisions, it can divide no further and then
it enters the cellular aging process. Thus our organs too have a finite
life span, given that they are composed of cells whose function eventually
declines. Stem cells, however, have unlimited potential to divide, and virtually
unlimited potential uses within the body. Scientists speculate that stem
cells thus constitute a largely untapped "fountain of youth,"
which, if harnessed, could conceivably allow us to rejuvenate our tissues
as needed, thus prolonging our lives.
A major consequence of aging is the aging of our tissues, and the inability
of our bodies to replace those aging tissues. Some of the diseases of
aging to which researchers hope to apply stem cell technology include
neurological disorders, including Parkinson's and Alzheimer's disease,
spinal cord damage and strokes; heart disease; diabetes; burns; and arthritis,
both rheumatoid and osteoarthritis. Culture of sufficient numbers of multipotent
stem cells could conceivably be used in place of whole organs in transplantation.
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