Space travel good for health?
An international team of scientists has shown that travelling into space can help a microscopic worm live longer.
Experiments carried out by researchers from Canada, France, Japan, the United Kingdom and the United States show that when the Caenorhabditis elegans (C. elegans) worm is sent into space the accumulation of toxic proteins, that normally accumulate within ageing muscle, was suppressed.
Writing in the journal Scientific Reports, the team also discovered a group of genes that are expressed at lower levels during spaceflight, and when the expression of these same genes is lowered in worms back on Earth the worms tended to live longer.
The aim of the research was to study the worms so as to further our knowledge of loss of bone and muscle mass experienced by astronauts after extended flights in space. C. elegans is the perfect substitute for studying long-term changes in human physiology because they suffer from muscle loss under many of the same conditions as humans. C. elegans was the first multi-cellular organism to have its genetic structure completely mapped and many of its 20,000 genes perform exactly the same functions as those in humans. Two-thousand of these genes have a role in promoting muscle function and 50 to 60% of these have very clear human equivalents.
To boot, C. elegans worms can live and reproduce for at least six months in space, making them an ideal and cost-effective experimental system to investigate the effects of long duration and distance space exploration. This research being carried out in space teaches us things about the human body we can't find out on Earth.
One of the study authors, Dr Nathaniel Szewczyk from the University of Nottingham in the United Kingdom, comments: 'We identified seven genes, which were down-regulated in space and whose inactivation extended lifespan under laboratory conditions.'
Although the scientists are not 100% certain how these genes play a role in longevity control they do think that these genes are involved in how the worm senses the environment and signals changes in metabolism in order to adapt to the environment.
Dr Szewczyk cites an 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.'
Dr Szewczyk discusses the implications of these findings for space explorers: '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. Counter-intuitively, muscle in space may age better than on Earth. It may also be that spaceflight slows the process of aging.'
The experiment, which took place in 2004, saw a consignment of live worms dispatched to the International Space Station (ISS) onboard the Dutch DELTA mission.
They have since taken part in five other spaceflights to the ISS with the aim of learning more about the effect of microgravity on the physiology of the human body.
In 2003, Dr Szewczyk's C. elegans worms hit the headlines when they survived the Space Shuttle Columbia disaster unscathed. They were recovered several weeks after the disaster still in the petri dishes where they had been living; as they were enclosed in aluminium canisters they were able to survive re-entry.
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Document Reference: Honda, Y., et al. 'Genes down-regulated in spaceflight are involved in the control of longevity in Caenorhabditis elegans', Scientific Reports, 2012. doi:10.1038/srep00487
Subject Index: Coordination, Cooperation; Life Sciences; Medicine, Health; Scientific Research; Space & satellite research