Living in space can extend an organism's lifespan - if that organism's a microscopic worm, at least.
An international team studying the loss of bone and muscle mass experienced by astronauts after extended flights in space has observed genetic changes in Caenorhabditis elegans that they say help it to live longer.
The ICE-FIRST team sent a consignment of live worms to the International Space Station (ISS) in 2004 onboard the Dutch DELTA mission.
And they found that spaceflight suppressed accumulation of toxic proteins that normally accumulate within aging muscle. They also discovered a group of genes that are expressed at lower levels during spaceflight. And when the expression of these same genes was lowered back on Earth, the worms lived longer.
"We identified seven genes, which were down-regulated in space and whose inactivation extended lifespan under laboratory conditions," says Dr Nathaniel Szewczyk, from the University of Nottingham.
"We are not entirely certain, but it would appear that these genes are involved in how the worm senses the environment and signals changes in metabolism in order to adapt to the environment. For example, one of the genes we have identified encodes insulin which, because of diabetes, is well known to be associated with metabolic control. In worms, flies, and mice insulin is also associated with modulation of lifespan."
C. elegans makes a good substitute for studying long-term changes in human physiology because it suffers from muscle atrophy under many of the same conditions as people do.
It was the first multi-cellular organism to have its genetic structure completely mapped, and many of its 20,000 genes perform the same functions as those in humans. Two thousand of these genes have a role in promoting muscle function, and 50 to 60 per cent of these have very obvious human counterparts.
He uses worms which originate from a garbage dump in Bristol. C. elegans often feed on decaying fruit and vegetable matter.
"Most of us know that muscle tends to shrink in space. These latest results suggest that this is almost certainly an adaptive response rather than a pathological one," says Szewczyk.
"Counter-intuitively, muscle in space may age better than on Earth. It may also be that spaceflight slows the process of ageing."