Spaceflight may age immune system in astronauts prematurely

WASHINGTON: Long-duration spaceflight may age the immune system in astronauts prematurely, a new study on mice suggests.

Researchers found that mice in low gravity conditions experience changes in B lymphocyte production in their bone marrow similar to those observed in elderly mice living in Earth conditions.

"This study shows that a model of spaceflight conditions could not only be used to test the efficacy of molecules to improve immune responses following a spaceflight in astronauts, but also in the elderly and bed-ridden populations on Earth," said researcher Jean-Pol Frippiat.

"This model could also help understand the ageing of the immune system called immunoscenescence," said Frippiat from the Stress, Immunity and Pathogens Laboratory at Lorraine University in Vandoeuvre-les-Nancy, France.

Frippiat and colleagues in the study used a ground-based model called hindlimb unloading (or HU), that simulates some of the effects of spaceflight on mice.

They analysed both bone parameters and the frequency of cells that will give birth to B lymphocytes in the bone marrow of young mice, old mice and mice subjected during three weeks to hindlimb unloading.

Comparison of these data revealed that bone changes and changes in the production of B lymphocytes in the bone marrow of HU mice were very similar to those observed in old mice.

The study, published in The FASEB Journal, shows that HU could be interesting to improve understanding of the relationship between bone remodelling and B cell production in the bones, both in the context of spaceflight and normal ageing on Earth, researchers said.

This model could therefore be used to test and/or develop molecules and compounds to improve immune responses following spaceflight in astronauts or in elderly and bed-ridden populations.

"Getting to Mars and beyond promises to be a huge task, requiring contributions from almost every scientific discipline," said Gerald Weissmann, Editor-in-Chief of The FASEB Journal.

"For biologists and medical researchers, knowing how altered gravity affect our immune system from challenges aloft can be already be studied on Earth. Fortunately for biologists, it's not rocket science," he said.