Research uncovers potential health risks of travel to Mars

March 8, 2017
Mars
Credit: NASA

Sending a manned mission to Mars requires more than a powerful launch rocket. Prep work also includes learning how a three-year space flight could affect the human body. With funding from the National Aeronautics and Space Administration (NASA), researchers at the Wake Forest Institute for Regenerative Medicine and colleagues are using human stem cells to measure the effects of deep space radiation.

Using mice transplanted with human , the research team has demonstrated for the first time that the encountered in travel may increase the risk of leukemia in humans.

"Our results are troubling because they show radiation exposure could potentially increase the risk of leukemia in two ways," said Christopher Porada, Ph.D., associate professor of and senior researcher on the project.

As part of this ongoing project, the group has identified and is currently testing a common dietary supplement for its ability to protect astronauts from these damaging effects.

"It is rewarding to use our expertise in stem to help NASA evaluate the potential health risks of space travel and hopefully develop strategies to address them," said Porada.

Radiation exposure is believed to be one of the most dangerous aspects of traveling to Mars, according to NASA. The average distance to the red planet is 140 million miles, and a roundtrip could take three years.

The goal of the study, published in the journal Leukemia, was to assess the direct effects of simulated solar energetic particles (SEP) and galactic cosmic ray (GCR) radiation on human (HSCs). These stem cells comprise less than 0.1% of the bone marrow of adults, but produce the many types of blood cells that circulate through the body and work to transport oxygen, fight infection, and eliminate any malignant cells that arise.

For the study, human HSCs from healthy donors of typical astronaut age (30-55 years) were exposed to Mars mission-relevant doses of protons and iron ions—the same types of radiation that astronauts would be exposed to in deep space—at the NASA Space Radiation Laboratory at Brookhaven National Laboratory. Researchers at the Wake Forest Institute for Regenerative Medicine then performed laboratory and animal studies to define the impact of the exposure.

These exposure levels that simulated deep space radiation were found to dramatically affect the health and function of the HSCs. "Radiation exposure at these levels was highly deleterious to HSC function, reducing their ability to produce almost all types of blood cells, often by 60-80 percent," said Porada. "This could translate into a severely weakened immune system and anemia during prolonged missions in deep space." Previous studies by other researchers had already demonstrated that exposure to high doses of earthly radiation, such as from X-rays, can have harmful (even life-threatening) effects on the body's ability to make blood cells, and can significantly increase the likelihood of cancers, especially leukemias. However, the current study was the first to show a damaging effect of low, mission-relevant doses of space radiation.

The current study is significant because it shows that radiation affected cells at the stem cell level. It caused mutations in genes involved in the hematopoietic process, and it dramatically reduced the ability of HSCs to give rise to mature blood cells.

The next step was to assess how the cells would function in the body. Mice were transplanted with GCR-irradiated human HSCs, essentially "humanizing" the animals. The mice developed what appears to be T-cell acute lymphoblastic leukemia - the first demonstration that exposure to may increase the risk of leukemia in humans.

"Our results show could potentially increase the risk of leukemia in two ways," said Porada. "We found that genetic damage to HSCs directly led to leukemia. Secondly, radiation also altered the ability of HSCs to generate T and B cells, types of white involved in fighting foreign 'invaders' like infections or tumor cells. This may reduce the ability of the astronaut's immune system to eliminate that arise as a result of radiation-induced mutations."

Porada said the findings are particularly troubling given previous work showing that conditions of weightlessness/microgravity present during spaceflight can also cause marked alterations in astronaut's immune function, even after short duration missions in low earth orbit, where they are largely protected from cosmic radiation. Taken together, the results indicate that the combined exposure to microgravity and SEP/GCR radiation that would occur during extended deep space missions, such as to Mars, could potentially exacerbate the risk of immune-dysfunction and cancer.

NASA's Human Research Program is exploring not only the effects of radiation, but also conditions of microgravity, isolation and confinement, hostile and closed environments, and distance from earth. The ultimate goal of the research is to make space missions as safe as possible.

Explore further: Changing the environment within bone marrow alters blood cell development

More information: C Rodman et al. In vitro and in vivo assessment of direct effects of simulated solar and galactic cosmic radiation on human hematopoietic stem/progenitor cells, Leukemia (2016). DOI: 10.1038/leu.2016.344

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4 comments

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entrance
5 / 5 (1) Mar 08, 2017
We still know very little about our solar system and all its dangers. It would be better to build a small base on Moon, before we try to conquer Mars. Our scientists would be able to react much faster, if problems arise. And of course it would be much cheaper.
rrrander
not rated yet Mar 08, 2017
Project Orion ships can be built thick enough (10,000 tons) to provide shielding from cosmic rays. The health issues from bombardment would be eliminated. But crummy, tin-can chemical rockets with paper-thin aluminum skins are death traps for a number of reasons.
michael_frishberg
1 / 5 (2) Mar 08, 2017
Even if we can survive the trip to Mars, there is almost no reason we should go in the first place.

Here's why:
We don't even know how to save ourselves from the the Biosphere's imminent inability to nurture human life.

NOTHING HUMANS DO IS SUSTAINABLE, ECOLOGICALLY SPEAKING.

If we can't save ourselves from ourselves, and don't understand our current ecological niche, how the hell can we sustain ourselves on Mars?

By 2100 there will be no mammals left on Planet Earth, and nothing we can do will change that. BTW, Humans are mammals, fyi.

Therefore, no one, anywhere, should have children, anymore.

vhemt.org - the only moral choice, to minimize the population when we crash and burn.
BubbaNicholson
1 / 5 (1) Mar 11, 2017
As a first step, stop sending functional spacecraft filled with waste/shielding to burn up in the atmosphere. It not only pollutes the earth's atmosphere, it is wasteful of energy, not to mention spacecraft. Give the ISS garbage bags and let them pile up a dump close by the station in the form of a wing to drive it upward propelled by solar winds. The cost of station keeping of the mass will be far less than the cost of replacing that mass with more mass for shielding interplanetary and interstellar spacecraft when that time comes. Such a dump, properly instrumented, would be a great detector anyway.

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