It's said that being an astronaut is no longer a bold endeavor. The job works program nature of NASA and a no-risk approach to missions by government has meant a drop in prestige among the public. It used to be risky and that captured the public's imagination.

Some day, if presidents stop canceling the space programs of their predecessors, man may leave orbit again, and astronauts will gain some new respect, because even if the mission is successful astronauts are paying a price - their cells are aging faster in microgravity.

Experiments conducted on the International Space Station involving cells that line the inner surfaces of blood vessels (endothelial cells) show that microgravity accelerates cardiovascular disease and the biological aging of these cells.  

"Understanding the cellular and molecular events of senescence might help in finding preventive measures that are useful to improve the quality of life of millions of people," said senior author Silvia Bradamante, a researcher involved in the work from the CNR-ISTM, Institute of Molecular Science and Technologies in Milan, Italy. "Our study further supports the role of oxidative stress in accelerating aging and disease."

In the report, Bradamante and colleagues examined endothelial cells in real microgravity aboard the International Space Station and conducted deep gene expression and protein analysis on the cells. They compared space-flown endothelial cells to endothelial cells cultured under normal gravity, looking for differences in gene expression and/or in the profile of secreted proteins. Space-flown cells differentially expressed more than 1,000 genes and secreted high amounts of pro-inflammatory cytokines. Ultimately, this induced significant oxidative stress, causing inflammation among endothelial cells, which in turn, led to atherosclerosis and cell senescence (biological aging).

Citation: Silvia Versari, Giulia Longinotti, Livia Barenghi, Jeanette Anne Marie Maier, and Silvia Bradamante, 'The challenging environment on board the International Space Station affects endothelial cell function by triggering oxidative stress through thioredoxin interacting protein overexpression: the ESA-SPHINX experiment ', FASEB J November 2013 27:4466-4475, doi:10.1096/fj.13-229195