A new study poses the question, ‘When does aging really begin?’ One glance in the mirror every morning is enough for me to know that regardless of where it begins I know where it’s going. And it’s not pretty.
But enough about me. Getting back to the question about aging, two researchers at Northwestern University have uncovered some clues that may give us a deeper understanding of aging and longevity, and even lead to new ways of improving quality of life as we get older.
The researchers were focused on C. elegans, a transparent roundworm. They initially thought that aging was a gradual process: that it began slowly and then picked up pace as the animal got older. Instead they found that in C. elegans aging begins just as soon as the animal reaches reproductive maturity. It hits its peak of fertility, and it is all downhill from there.
The researchers say that once C. elegans has finished producing eggs and sperm – ensuring its line will continue – a genetic switch is thrown by germline stem cells. This flipped switch begins the aging process by turning off the ‘heat shock response’; that’s a mechanism the body uses to protect cells from conditions that would normally pose a threat or even be deadly.
In a news release Richard Morimoto, the senior author of the study, says that without that protective mechanism in place the aging process begins:
“C. elegans has told us that aging is not a continuum of various events, which a lot of people thought it was. In a system where we can actually do the experiments, we discover a switch that is very precise for aging. All these stress pathways that insure robustness of tissue function are essential for life, so it was unexpected that a genetic switch is literally thrown eight hours into adulthood, leading to the simultaneous repression of the heat shock response and other cell stress responses.”
You read that right. In the case of poor old C. elegans the aging process begins just eight hours into adulthood. Of course the lifespan of the worm is only about 3 weeks so it’s not surprising the aging process kicks in quite so quickly.
To further test their findings the researchers carried out an experiment where they blocked the genetic switch from flipping, and the worm’s protective mechanisms remained strong.
Now, taking findings from something as small as a worm and trying to extrapolate them to larger animals is never easy. Nonetheless understanding what triggers aging in C. elegans could help us figure out if a similar process was taking place at the cellular level in people.
Morimoto says that knowledge might help us develop ways to improve our cellular quality of life and delay the onset of many of the diseases of aging:
“Wouldn’t it be better for society if people could be healthy and productive for a longer period during their lifetime? I am very interested in keeping the quality control systems optimal as long as we can, and now we have a target. Our findings suggest there should be a way to turn this genetic switch back on and protect our aging cells by increasing their ability to resist stress.”
The study is published in the journal Molecular Cell.