Human Minibrains Sent to Space Thrived in an Unexpected Manner

Human minibrains, or organoids, launched into space surprised scientists by thriving during their time in low-Earth orbit. In 2019, US researchers sent lab-grown human neural tissue to the International Space Station (ISS) for a brief stay. The result was nothing short of astonishing.

The cells not only survived the weightlessness of space for weeks, but they also matured faster than similar cells grown on Earth. “The fact that these cells survived in space was a big surprise,” says Jeanne Loring, molecular biologist at the Scripps Research Institute. “This lays the groundwork for future space experiments involving brain regions affected by neurodegenerative diseases.”

The ISS offers a unique research opportunity to study microgravity’s effects on human cells. This has implications not only for astronauts but also for human health research and disease modeling. Led by molecular biologist Davide Marotta of the ISS National Laboratory, a team investigated how microgravity affects the human brain, focusing on neurons impacted by neurodegenerative diseases like Parkinson’s and multiple sclerosis.

The researchers grew organoids using human induced pluripotent stem cells from both healthy donors and patients with neurodegenerative conditions. These stem cells, derived from adult human cells, were reverted to an earlier developmental stage and then induced to form neurons—specifically cortical or dopaminergic neurons, which are affected by diseases like Parkinson’s.

Organoids with Microglia Sent to Space for Analysis After a Month in Orbit

Some organoids also contained microglia, brain immune cells. These organoids were placed in cryovials, divided into two groups—one sent to space and the other kept on Earth. After a month in orbit, the organoids returned to Earth for analysis.

The survival of the organoids was a surprising result in itself. However, there were also notable differences between the space-grown and Earth-grown organoids. Not only did the space organoids show increased gene expression related to cell maturation, but they also had slower cell replication rates compared to their Earth counterparts.

Interestingly, the space organoids expressed fewer stress-related genes and showed less inflammation than expected. This suggests that microgravity, which is devoid of convection, may create conditions that resemble the brain’s natural environment more closely than Earth-based laboratory conditions. “In space, these organoids are more like the brain,” Loring explains. “They don’t get flushed with culture medium or oxygen; they form a brain-like microcosm.”

These findings suggest microgravity may provide a more natural environment for studying brain cells’ responses to stressors or treatments. Looking ahead, the researchers plan to explore brain regions affected by Alzheimer’s disease and investigate how neurons connect in space. As Loring notes, “We’re at the ground floor—literally in the sky, but on the ground floor of something new.”

Read Original Article: Science Alert

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