Becoming an astronaut is something that many people dream of, yet the long-term effects of space travel are often overlooked.
Microgravity presents a serious issue for astronauts during long-term space flight, decreasing bone density and increasing the risk of bone fractures.
Now, researchers believe they may have a way of protecting astronauts against bone loss during long space missions – gene-edited lettuce.
Experts from the University of California, Davis have developed transgenic lettuce that has been genetically engineered to produce a bone-stimulating hormone, and say it could be grown in space.
While safety restraints mean they’re yet to give the important ‘taste test’ to the lettuce, the team says it’s likely it will taste very similar to its regular counterpart.
Experts from the University of California, Davis claim that transgenic lettuce that has been genetically engineered to produce a bone-stimulating hormone could be grown in space
Microgravity presents a serious issue for astronauts during long-term space flight, decreasing bone density and increasing the risk of bone fractures. Now, researchers believe they may have a way of protecting astronauts against bone loss during long space missions – gene-edited lettuce
Previous research has confirmed that during long space missions, astronauts suffer from a condition known as osteopenia, which causes the bones to weaken.
‘Weakening of the bones due to the progressive loss of bone mass is a potentially serious side-effect of extended spaceflight,’ NASA said.
‘Studies of cosmonauts and astronauts who spent many months on space station Mir revealed that space travellers can lose (on average) 1 to 2 percent of bone mass each month.’
To counter this effect, astronauts on board the International Space Station (ISS) have certain exercise regimens they follow.
However, astronauts are not typically on the ISS for longer than six months.
Looking ahead, NASA is planning to send humans to Mars sometime in the 2030s – a mission that will last at least three years and will put them at higher risk for osteopenia.
One option would be for astronauts to take medication containing a peptide fragment of human parathyroid hormone (PTH), which stimulates bone formation.
However, transporting large quantities of the medication is not practical.
In their new study, the team looked at ways for astronauts to produce the peptide fragment themselves while in space.
Their solution is transgenic lettuce seeds that have been genetically edited to produce the PTH.
‘Astronauts can carry transgenic seeds, which are very tiny — you can have a few thousand seeds in a vial about the size of your thumb — and grow them just like regular lettuce,’ said Dr Somen Nandi, one of the authors of the study.
‘They could use the plants to synthesize pharmaceuticals, such as PTH, on an as-required basis and then eat the plants.’
Astronauts on board the International Space Station (ISS) have certain exercise regimens. However, astronauts are not typically on the ISS for longer than six months. Pictured: Flight engineer and European Space Agency (ESA) astronaut Samantha Cristoforetti exercises on the Advanced Resistive Exercise Device
A piece of a protein called a fragment crystallizable (Fc) domain was attached to the peptide.
Fc has has previously been shown to increase the time peptides circulate in the body, making it more effective.
Then, to introduce the peptide and Fc (together known as PTH-Fc) to the lettuce, the researchers used a species of bacteria called Agrobacterium tumefaciens.
During screening, the researchers found that the lettuce expressed about 10-12 milligrams of PTH-Fc per kilogram.
This means that astronauts would need to about eight cups (380 grams) of lettuce a day to get a sufficient dose of the hormone.
For context, a standard head of lettuce weighs around 300 grams.
‘One thing we’re doing now is screening all of these transgenic lettuce lines to find the one with the highest PTH-Fc expression,’ explained Dr Karen McDonald, one of the researchers on the project.
‘We’ve just looked at a few of them so far, and we observed that the average was 10-12 mg/kg, but we think we might be able to increase that further.
‘The higher we can boost the expression, the smaller the amount of lettuce that needs to be consumed.’
Unfortunately, due to safety constraints, the researchers have been unable to taste the lettuce.
However, they anticipate that it’s likely to taste very similar to its regular counterpart.
The team now plans to send their transgenic lettuce seeds to the ISS to see how they grow in space.
Kevin Yates, a researcher on the project, added: ‘I would be very surprised that if, by the time we send astronauts to Mars, plants aren’t being used to produce pharmaceuticals and other beneficial compounds.’
EXPLAINED: THE $100 BILLION INTERNATIONAL SPACE STATION SITS 250 MILES ABOVE THE EARTH
The International Space Station (ISS) is a $100 billion (£80 billion) science and engineering laboratory that orbits 250 miles (400 km) above Earth.
It has been permanently staffed by rotating crews of astronauts and cosmonauts since November 2000.
Crews have come mainly from the US and Russia, but the Japanese space agency JAXA and European space agency ESA have also sent astronauts.
The International Space Station has been continuously occupied for more than 20 years and has been expended with multiple new modules added and upgrades to systems
Research conducted aboard the ISS often requires one or more of the unusual conditions present in low Earth orbit, such as low-gravity or oxygen.
ISS studies have investigated human research, space medicine, life sciences, physical sciences, astronomy and meteorology.
The US space agency, NASA, spends about $3 billion (£2.4 billion) a year on the space station program, with the remaining funding coming from international partners, including Europe, Russia and Japan.
So far 244 individuals from 19 countries have visited the station, and among them eight private citizens who spent up to $50 million for their visit.
There is an ongoing debate about the future of the station beyond 2025, when it is thought some of the original structure will reach ‘end of life’.
Russia, a major partner in the station, plans to launch its own orbital platform around then, with Axiom Space, a private firm, planning to send its own modules for purely commercial use to the station at the same time.
NASA, ESA, JAXA and the Canadian Space Agency (CSA) are working together to build a space station in orbit around the moon, and Russia and China are working on a similar project, that would also include a base on the surface.
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