Researchers at the University of Rochester Medical Center Department of Neurobiology and Anatomy are concerned that space radiation may hasten the start of Alzheimer’s disease. While the effects of prolonged space travel have long been discussed by scientists, this is the first study to reveal that space radiation could lead to alterations in the brain that are linked to Alzheimer’s disease.
“Galactic cosmic radiation poses a significant threat to future astronauts,” said senior author M. Kerry O’Banion, a professor in the URMC Department of Neurobiology and Anatomy, in a statement. “The possibility that radiation exposure in space may give rise to health problems such as cancer has long been recognized. However, this study shows for the first time that exposure to radiation levels equivalent to a mission to Mars could produce cognitive problems and speed up changes in the brain that are associated with Alzheimer’s disease.”
According to researchers, there are some forms of space radiation that cannot be effectively blocked. This means that astronauts are exposed to a constant shower of radioactive particles as soon as they leave orbit (while in low Earth orbit, the planet’s magnetic field generally shields astronauts from these harmful particles). The more time an astronaut spends in deep space, the greater the exposure.
The researchers looked at the impact of a form of radiation called high-mass, high-charge (HZE) particles. HZE particles are shot through space at extremely high speeds by the force of exploding stars. For this particular study, researchers examined iron particles. The mass of HZE particles like iron, combined with their speed, allow them to penetrate the wall and protective shielding of a spacecraft, leaving an astronaut all but defenseless against harmful space radiation.
“Because iron particles pack a bigger wallop it is extremely difficult from an engineering perspective to effectively shield against them,” said Dr. O’Banion. “One would have to essentially wrap a spacecraft in a six-foot block of lead or concrete.”
The researchers exposed animals to various doses of radiation, attempting to mimic the levels that astronauts would experience during a mission to the Red Planet. The researchers found that the mice exposed to radiation were far more likely to fail at recalling objects or specific locations.
The brains of the mice also revealed a higher than normal accumulation of beta amyloid, the protein “plaque” that accumulates in the brain and is one of the telltale signs of the disease.
“These findings clearly suggest that exposure to radiation in space has the potential to accelerate the development of Alzheimer’s disease,” said Dr. O’Banion. “This is yet another factor that NASA, which is clearly concerned about the health risks to its astronauts, will need to take into account as it plans future missions.”
In order to learn more about space radiation and its impact on astronauts on deep space missions, The Space Reporter conducted an interview with Dr. O’Banion via email. A transcript of our conversation can be found below:
The Space Reporter (TSR): Are there ways to protect the human brain from space radiation?
Dr. O’Banion: Effective shielding, though this is problematic in deep space flight because of weight restrictions on spacecraft. To my knowledge there are no clear pharmacologic or other approaches to protect the brain, though a number of groups are working on this.
TSR: Do you think that this study’s findings, if backed up by additional research, will convince NASA to reconsider sending a manned mission to Mars?
Dr. O’Banion: Our findings represent a very small part of the overall challenge NASA faces in mounting such a mission. There are so many factors (including costs) in play that I doubt our results will sway the process very much. Their importance is really in helping us to understand what the potential risks might be so that they might be addressed.
TSR: What was the motivation for this study?
Dr. O’Banion: My lab group has studied factors that influence Alzheimer’s disease pathology for 20 years and radiation effects on the brain for the past 10 years. In recent years NASA asked for research targeted at understanding whether space radiation might contribute to neurodegenerative disease. Thus for us it was a natural progression to the current study.
TSR: Are you conducting any additional research on this topic?
Dr. O’Banion: Yes, I have a grant with NASA to examine several other mouse models of neurodegenerative disease following space radiation exposure.
This study comes as NASA is preparing for a manned mission to the Red Planet. Currently, NASA plans on sending a manned mission to Mars in the 2030s, according to NASA Administrator Charles Bolden. This study, as well as other challenges, may convince the space agency to reconsider this timeline.
The study’s findings were recently described in detail in the journal PLOS ONE.