Story at a glance
- Researchers sent human cells to the International Space Station.
- In parallel experiments in space and on the ground, some cells were infected with salmonella.
- The scientists found evidence that changes in the cells brought on by a microgravity environment may lead to salmonella being more virulent in space.
In a new study published in the journal npj Microgravity, scientists and astronauts conducted experiments with human cells and pathogens to see how the two would change and interface differently in a low-gravity environment. The researchers used the microbial species salmonella typhimurium to infect human cells in controlled experiments on Earth and on the International Space Station.
The researchers found that there were changes in RNA and protein expression in the human cells in a microgravity environment. They also found that salmonella was able to cause the human cells to upregulate — increase the rate or level of — expression of compounds that would help fight an infection in both cells that were inflight and on the ground.
Inflight cells upregulated genes that were associated with inflammation, one of the human body’s mechanisms for fighting pathogens. Other genes that are related to virulence or stress regulators were also upregulated in the cells in space compared to the cells on the ground.
"We appreciate the opportunity that NASA provided our team to study the entire infection process in spaceflight, which is providing new insight into the mechanobiology of infectious disease that can be used to protect astronaut health and mitigate infectious disease risks," said one of the study’s authors Cheryl Nickerson, who is based at the Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, in a press release. "This becomes increasingly important as we transition to longer human exploration missions that are further away from our planet."
There were limitations to the study; not all samples that came back from space were able to be analyzed as fully as the scientists were hoping to. There were also small differences in the amount of pathogen administered to cells on the ground compared to inflight.
Still, this study’s findings are a good start to understanding how infections in space might affect our bodies. Scientists will need to know a lot more about the body’s response to a variety of pathogens, not just salmonella. This is all so that in the future humans may be able to spend more time in space and on longer flight missions.
"We knew that spaceflight also impacted several important structural and functional features of human cells that Salmonella normally exploits during infections on earth," the study’s lead author Jennifer Barrila, who is also based at the Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, said in the press release. "Our study indicates that there are some pretty big changes in the molecular landscape of the intestinal epithelium in response to spaceflight, and this global landscape appears to be further altered during infection with Salmonella."
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