A team of scientists sent organoids to the International Space Station to understand the effects of space travel on the brain.
Microgravity is known to alter muscles, bones, the immune system and cognition, but little is known about its impact on the brain.
To discover how brain cells respond to microgravity, scientists at Scripps Researchin collaboration with the New York Stem Cell Foundationsent small clusters of stem cell-derived brain cells, called “organoides”, for the International Space Station (ISS).
When they returned to Earth, after a month in space, the organoids remained healthy, but presented a faster maturation than those grown on our planet. In essence, the cells were closer to becoming adult neurons and began to show signs of specialization.
This discovery may help to understand how space travel affect the nervous system. In , Jeanne Loring said that “the fact that these cells survived in Space was a huge surprise,” a discovery that “paves the way for future experiments in which we can study other parts of the brain affected by neurodegenerative diseases”.
Maturity does not mean aging
The team used stem cells to create organoids composed of cortical or dopaminergic neurons, both of which are involved in diseases such as multiple sclerosis and Parkinson’s. Some of them also included microglia, the brain’s immune cells, to look at the impact of microgravity on brain inflammation.
Typically, organoids are grown in a liquid nutrient medium, but to avoid extra work on the ISS, the team created smaller organoids that were stored in cryos, airtight vials designed for deep freezing.
These organoids were prepared at the Kennedy Space Station, a NASA laboratory, and sent to the International Space Station in an incubator. They returned intact and healthy after a month-long stay.
Once on Earth, the scientists compared the gene expression of the organoids in space with those of the control group, grown on Earth. The surprise came when we discovered that cells exposed to microgravity matured more quickly, with greater expression of genes associated with maturity and fewer genes related to cell proliferation. This means that they developed faster and divided less than terrestrial organoids.
“It is important to highlight, however, that although the organoids matured, they did not become adult neurons, which means that the study does not reveal information about cellular aging,” Loring highlighted.
Contrary to expectations, the organoids grown in Space also showed less inflammation and lower expression of stress-related geneswhich suggests that the microgravity environment may have a calming effect on some brain cells.
The findings were published in Stem Cells Translational Medicine.
