Scientists Move Closer to Understanding Why We Age
by ilene - February 15th, 2010 11:18 pm
Scientists Move Closer to Understanding Why We Age
By Eben Harrell / London, courtesy of TIME
Time waits for no man, the old truism goes, but in recent years scientists have shown that it does seem to move more slowly for some. Molecular biologists have observed that people’s cells often age at different rates, leading them to make a distinction between "chronological" and "biological age."
But the reason for the difference remains only vaguely understood. Environmental factors such as smoking, stress and regular exercise all seem to influence the rate at which our cells age. Now, for the first time, researchers have found a genetic link to cellular aging — a finding that suggests new treatments for a variety of age-related diseases and cancers.
The field of "biological aging" has in recent years focused on the long molecules of DNA contained in human cells called chromosomes. All chromosomes have protective caps at either end called telomeres. Each time a cell replicates itself (as it does before it dies), the telomeres shorten, like plastic tips fraying on the end of shoelace. Shortened telomeres have been linked to a host of age-related illnesses such as heart disease and certain cancers. (Scientists have yet to study whether telomeres influence a person’s appearance). Last year’s Nobel prize in medicine was awarded to three American scientists for their work in the field, and many scientists now believe telomeres are the closest we may come to identifying a biological clock — and our best bet for one day learning how to stop or turn back that clock.
To better understand the aging discrepancy, a team of researchers in Britain and The Netherlands scanned more than 500,000 genetic variations across the human genome. Using a population of nearly 12,000, they then attempted to pinpoint a genetic link to telomere length. (See how to prevent illness at any age.)
In a significant breakthrough, the team successfully identified that a particular gene sequence was associated with differences in telomere length between individuals. What’s more, the sequence was clustered near a gene called TERC, which is already known to play a role in the production of an enzyme called telomerase. Telomerase repairs telomeres when they shorten. "That was very exciting for us," says Professor Nilesh Samani, a cardiologist at the University of Leicester who co-led the research, published last week in Nature Genetics. "It gave us great…
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