En español | If there were a test that could predict your vulnerability to disease and how quickly you will age, would you take it?
This year, several companies will be selling tests — available through doctors — that measure telomeres, key genetic markers that researchers have linked to health and longevity. The science behind them is so tantalizing that some have touted the tests as the key to understanding mortality. But a number of researchers contend that the science is still far too young for test results to be truly revealing. Tests should not be used, they argue, outside a research setting.
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Even two of the scientists who shared the 2009 Nobel Prize for their telomere research differ on whether a telomere test can currently be used to predict long-term health. Although both believe that analyzing telomeres will become an important medical tool over the next 10 to 20 years, they split over whether we know enough about these structures now to use them to gauge health and aging.
One of the Nobel Prize winners, Elizabeth H. Blackburn of the University of California, San Francisco, has cofounded a company — Telome Health — to offer a telomere test to the public. The other, Carol Greider of Johns Hopkins University, says a lot more research is needed to understand the relationship between telomeres and disease.
So what are telomeres and should you have yours measured?
Telomeres are the protective caps on the ends of the chromosomes that keep them from fraying when cells divide. Scientists know that telomeres shorten as people age, and that eventually telomeres become so short that the cells cannot reproduce, and they die. Also, certain diseases that cause rapid, repeated cell division are known to shorten telomeres. Studies have linked increasing numbers of short telomeres to a shorter life span and to the development of age-related diseases, including lung disease, heart disease, diabetes and cancer.
Scientists are years away from being able to lengthen telomeres in humans, but some research in mice shows promise. In 2010 Harvard-affiliated scientists genetically engineered mice to age quickly by turning off the enzyme that maintains telomeres. When they reactivated that enzyme, it led to dramatic reversals in age-related diseases. The researchers expected the aging process to slow or even stop, but the experiment actually reversed the aging process. The mice began to regrow tissue in the spleen, testes and brain.
"It was akin to a Ponce de Leon effect," senior researcher Ronald DePinho, who is now president of the University of Texas MD Anderson Cancer Center, told the Harvard Gazette. Scientists may have not found the mythical Fountain of Youth, but the possibilities that telomere research holds are intriguing.
"This unique biomarker might help people think more about prevention of disease and monitoring their health earlier in life," says Elissa Epel, a researcher at the University of California, San Francisco, who cofounded Telome Health. She says the goal of the tests is to monitor this marker, and individuals should view their results as simply "a risk factor just like any other risk factor."