Monday, February 21, 2011

What Doesn't Kill You Makes You Older

Elizabeth Blackburn of UC San Francisco is part of a three-person team that won the 2009 Nobel Prize in Physiology or Medicine for the 1978 discovery of telomerase, the enzyme that lengthens and stabilizes telomeres. (Telomeres are DNA-protein complexes that cap the ends of chromosomes. As Blackburn explains it, they function like the tips on shoe laces, and protect chromosomes from fraying. However, each time a cell divides, some of the telomeres are used up. Below a critical telomere length, the cell loses its ability to reproduce itself. By replenishing telomeres with each cell division, telomerase plays a critical role in cell health and life span.)

In a landmark study of mothers of chronically ill children that was published in 2004, Blackburn reported that the mothers with the longest-term stress (the mothers with the oldest chronically ill children) had chromosomes with the shortest telomere tips. She and fellow researchers attributed the shorter lengths to diminished serum levels of telomerase, and estimated that during their years of stress those mothers' white blood cells had prematurely aged by 9-17 years.

Now Blackburn is suggesting that the aging news is not all bad for the chronically stressed, for with knowledge comes power. In studies published in 2009 and 2010, some subjects studied actually enjoyed increased telomere length over time. These findings opened the door to the search for factors that can help people lengthen telomoeres. Studies published in 2010 pointed to meditation, exercise, and, for women, delayed menopause.

According to Blackburn, the take-home message for chronically-stressed people who don't want to prematurely fall prey to age-related illness and debility is this: "Work hard. Play harder."

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