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Is there a genetic clock for aging?
Check the latest research |
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On Telomeres and Age-Related Diseases and
Conditions |
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Much research is ongoing to find out just how telomere shortening contributes
to the process of aging and the development of age-related diseases. Shortened
telomeres have been found in a variety of human tissues, including aging
skin, skeletal muscle and central nervous system tissue.6 If
this shortening relates to the development of disease is still being examined.
 Heart
Disease
Liver
Diseases
Kidney
Disease
Immune
System Decline
Age-Associated
Inherited Diseases
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Heart Disease |
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As we age, our arteries lose their elasticity. Those arteries called
upon to deliver blood to our most critical organs are subject to the
most wear and tear. Because of this stress, these arteries have the
most cell turnover. Therefore, their telomeres shorten faster. Some
research has shown that those arteries with the shortest telomeres are
the ones with the most age-related deterioration.7
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Liver Diseases |
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Our livers have the reputation of being the organs with the greatest capacity
for self-repair after injury or illness. (Perhaps this explains why some
people seem to be able to abuse alcohol for years with apparent impunity.)
But this capacity for self-repair is not infinite. Chronic hepatitis,
cirrhosis and advanced age are all known to produce a reduction in liver
function. Japanese researchers have shown that telomere length in those
with chronic hepatitis, cirrhosis or even in healthy octogenarians is
substantially shorter than in healthy young adults. This suggests, though
doesn't prove, that the telomere shortening that occurs with each liver
cell division is what eventually leads to the aging and death of these
cells, and thus the aging and loss of function of the liver itself.8
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Kidney Disease |
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Unlike our livers, our kidneys possess less capacity for self-repair.
Age-related diseases like high blood pressure and heart failure reduce
kidney function, but so does aging itself. A healthy 80-year-old does
not generally have the kidney function of a healthy 30-year-old. A study
of the cells retrieved in a series of kidney biopsies revealed that shorter
telomeres correlated positively with advancing age, providing more evidence
that telomere shortening is a factor in age-related conditions.9
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Immune System Decline |
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Although the shortening of telomeres is associated with the decline in
cell function in a variety of conditions, other factors also play a part.
Some scientists have theorized that shortening of telomeres in the immune
system contributes to the decline in our ability to fight infectious disease
as we age. However, other studies have shown that mice and rats, whose
telomeres are much longer than ours, also experience age-related immune
decline. This has led some to speculate that factors other than telomere
shortening are responsible for immune decline with age. 10
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Age-Associated Inherited Diseases |
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Researchers are exploring the role telomeres may play in inherited diseases
that can take time to express themselves. Some people inherit a gene for
a disease from one parent and a healthy gene from the other. As they grow
and develop, their healthy gene predominates. Over time, however, the shortening
of their telomeres with successive cell divisions leads to all sorts of
cellular chaos, and defective genes then have the opportunity to manifest
themselves. This has been proposed as a possible factor in the development
of such diseases as type II diabetes and high blood pressure. 11
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