Astronauts at risk for Alzheimer's

As NASA sets the stage for increasingly ambitious trips into space, new research highlights a potential hazard for astronauts on long-range missions: Alzheimer's disease.

According to a new animal study published in PLoS ONE, the kind of cosmic radiation exposure faced by those on board flights heading toward the far-flung reaches of the galaxy has the potential to speed up the onset of the neurological disease.

"Galactic cosmic radiation poses a significant threat to future astronauts," senior study author Dr. M. Kerry O'Banion, a professor in the University of Rochester Medical Center's department of neurobiology and anatomy, said in a URMC news release.

"The possibility that radiation exposure in space may give rise to health problems such as cancer has long been recognized," he added. "However, this study shows for the first time that exposure to radiation levels equivalent to a mission to Mars could produce cognitive mental problems and speed up changes in the brain that are associated with Alzheimer's disease."

The authors point out that here on Earth the planet's magnetic field offers protection from space radiation. Once in deep space, however, all bets are off, with travellers exposed to a never-ending bath of low-level radioactive particles.

For the most, the bombardment is at a low enough level that short-term space travel is not overly concerning, the researchers say

Radiation exposure accelerates Alzheimer’s

The picture changes, however, when contemplating longer-term trips, such as one to Mars currently planned for 2035 and predicted to take about three years round-trip.

O'Banion, URMC graduate student Jonathan Cherry, the study's first author, and colleagues analysed the impact on from exposure to high-mass, high-charged iron particles, which move incredibly fast and are able to go right through most solid objects.

Mice exposed to doses deemed comparable to what astronauts would have to field during a trip to Mars were much more likely to fare poorly on a series of mental acuity tests than unexposed mice.

The brains of exposed mice displayed telltale evidence of Alzheimer's onset in the form of vascular alterations, as well as an uptick in the accumulation of a protein plaque called beta amyloid.

"These findings clearly suggest that exposure to radiation in space has the potential to accelerate the development of Alzheimer's disease," O'Banion said. "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."

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More information

For more on Alzheimer's, visit the U.S. National Institutes of Health.

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