Astronaut Blood Samples Continue To Shed Light On The Health Risks Of Spaceflight

Scientists are continuing to use a collection of decades old blood samples taken from space shuttle astronauts to understand the impacts of spaceflight stress on human health.

In a new study, a team of international researchers describe how they examined exosomes, vehicles within the cell that contain the building blocks of life, like DNA and RNA – a molecule which plays a role in gene expression. Analyzing samples from astronauts 10 days before spaceflight and again 3 days after they returned to Earth’s surface, all within the time period between 1998 to 2001, the team found a number of a type of RNA called microRNAs had changed their expression.

“I think we’re just starting to learn the value of these samples,” said Jennifer Fogarty, the chief scientific officer at the Translational Research Institute for Space Health which supported the research.

The new paper validates the use of the 20 year old blood samples for research, according to David Goukassian, a professor of medicine and cardiology at the Icahn School of Medicine at Mount Sinai and lead author of the study. Their study shows that the exosomes and the precious cargo they carry can be studied for decades because they are preserved within blood samples. “That may accelerate our ability for discovery and for development for the predictive biomarkers,” said Goukassian.

In March, Goukassian published a different study using the astronaut blood samples. The earlier study explored a different type of RNA called long non-coding RNA and found a number changed their expression under spaceflight stressors. Like the former study, the new study revealed changes in microRNA expression that are associated with a range of diseases.

“Our research has been trying to shed light on…the expression changes of these microRNAs in the astronauts before and after flight,” said Venkata Garikipati, an assistant professor in the department of emergency at the Ohio State University and co-author of the paper.

As Raj Kishore, the vice chair of the department of cardiovascular sciences at Temple University and a co-author on the paper explained, a person who displays the microRNA change in their blood “may be disposed to neurodegenerative diseases or maybe cancer or maybe cardiovascular disease in the future.”

Previously, NASA’s Twin Study documented identical twin astronauts Mark and Scott Kelly as Scott spent a year aboard the International Space Station and Mark spent the same time on the ground. The results of the Twin Study similarly documented Scott’s cells showed unique changes in microRNA.

Though the study is informative of the biological impacts of spaceflights stress, future studies will be needed to understand the true implications of the changes in expression of the microRNA that the team observed. Only three different astronaut blood samples were used for the study and the average flight duration was only 12 days. Having access to larger sample sizes and more clinical data in the future will allow researchers to better understand the changes in microRNA they saw – and what, if anything, scientists can do to mitigate the potential diseases they may cause.

Fogarty believes the work will open the door for other archival research samples to be used in studies. “The findings are really opening up a new area of research for NASA,” she said.

And, though the samples are associated with spaceflight, the research could have real-world implications as well. “It’s really about stress and people undergo stress all the time in their life,” said Fogarty. “I’m just hoping people that there’s a greater value than spaceflight here, that it really does come back to Earth.”

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