New drugs could make astronauts more resistant to cosmic rays that cause cancer during missions to Mars

Beyond Earth's protective magnetic shield, space-travelling humans are subjected to stronger radiation which puts astronauts at significant risk of radiation sickness, and an increased lifetime risk of developing cancer and degenerative diseases.

During their careers astronauts are typically exposed to an upper limit of between 800 and 1,200 milli-sieverts (mSv), a form of measurement used for radiation. One mSv is the equivalent of about three chest X-rays. One return trip to Mars would subject astronauts to 660 mSv, more than half of the career limit.

A cocktail of anti-ageing drugs which also combat radiation could be the solution, according to US scientists.

Dr Alex Zhavoronkov, CEO of Insilico Medicine, who is leading a research project involving an international group of scientists, including researchers from NASA, said: “The cost of one productive life year (PLY) for humans in space is likely to be much higher than on Earth and efforts should be made to maximise PLYs of the [Mars] colonists…High-LET (linear energy transfer) radiation is among the first challenges that needs to be addressed and productive longevity will likely be a side effect of increased radioresistance.”

Insilico, an artificial intelligence company focused on longevity biotechnology, has suggested radioprotectors – molecules that help protect the body against radiation – could limit that exposure. Research has found there are similarities between the DNA damage during ageing and DNA damage during radiation exposure. Many radioprotectors are anti-ageing.

Zhavoronkov said: “So, the same compounds that may be effective against ageing may also be effective against radiation, which is a nice bonus.

“Some of the radioprotectors include the isotopically-fortified organic molecules that comprise our cellular membranes and proteins. For example, isotopically-fortified Omega-3 taken over time may be effective against radiation-induced damage.”

Zhavoronkov said his company is working on radioresistance “to make radioresistant astronauts and space colonists”.

He said: “Now that Elon Musk is planning a mission to Mars and a colony, this new technology is very important because the humans will need to survive extended exposure to radiation.

“Also, since it is very expensive to launch humans into space, extending the longevity and increasing radiation resistance makes a lot of sense.”

Insilico research scientist Polina Mamoshina, who is working on the project, said: “We are in discussion with NASA about how to proceed because we are at the stage of validating and testing new prospective drugs and then we could partner with them, because NASA is super-interested in having something to prevent the harmful effect of radiation.”

Zhavoronkov added: “The key idea of the paper is that by making humans radiation resistant it is possible to make them live longer and more productive lives. And once the astronauts demonstrate the effectiveness of these techniques, it may even be possible to increase lifespan and improve radiation resistance of the general population.

“In today's turbulent world with the many nuclear plants and weapons, having the ability to protect against or respond to the radiation-induced damage may save many valuable lives.”

The strategy for achieving increased radioresistance and longevity will be presented at the 5th Annual Ageing Research for Drug Discovery Forum and the 2nd Annual Artificial Intelligence and Blockchain Technologies for Healthcare Forum in Basel as part of the Basel Life Congress in September.

Dr Alex Zhavoronkov, CEO of Insilico Medicine, explains the way the drugs will work…

Radioprotectors

These are molecules that help protect the body against radiation. Many of these radioprotectors are actually geroprotectors, senoremediators and senolytics.

Geroprotectors

Geroprotectors are the molecules with the demonstrated or predicted ability to slow down or even reverse one or several ageing processes. Some of the known ones include widely-used common drugs, including metformin and rapamycin that demonstrated life extension in animals. In addition to their geroprotective properties, many of these molecules have serious side effects and researchers all over the world are looking for safer and more effective alternatives. Some of the newer ones like nicotinamide, riboside (a form of vitamin B3) and Withaferin A (an active ingredient in Ashwagandha, a herb with restorative benefits) that come from natural sources are considered to be safe and effective and may also protect against radiation.

Senoremediators

Senoremediators are the molecules that return the cells back into a more youthful and productive state and prevent them from becoming fully-senescent. Natural molecules like myricetin, NAC and EGCG may be classified as senoremediators. But there are many pharmaceutical-grade molecules that have similar properties and also can be used for rescuing the cells that have been only mildly damaged by radiation.

Senolytics

Senolytic molecules intend to kill the fully-senescent cells. A very small number of our cells are fully-senescent. They don’t turn into cancer but occupy space without doing any productive work and pollute the microenvironment around them. These cells need to be cleared out. Some of the cells become senescent after exposure to radiation and can be cleared by senolytics. But it is important to first apply senoremediators before applying senolytics to ensure that only the fully-senescent cells are killed.