A recent groundbreaking study published on December 19, 2024, by researchers from the Scripps Research Institute in the United States has demonstrated that human brain cells can survive for extended periods in low Earth orbit. This discovery opens new avenues for developing treatments for neurodegenerative diseases.
In 2019, a team of American researchers sent clusters of lab-grown human neural tissue, known as 'organoids', to the International Space Station (ISS) for a month-long experiment. Upon their return, scientists found that the human neurons not only survived but also matured faster than those grown on Earth.
Dr. Jian Loring, a molecular biologist at Scripps, stated, 'The fact that these cells survived in space was a huge surprise. This paves the way for future space experiments where we can include other parts of the brain affected by neurodegenerative diseases.'
The ISS provides a unique opportunity for scientific research, allowing the study of the effects of microgravity on human cells, which has significant implications for both astronauts and health research on Earth. This research could also aid in modeling diseases and drug development.
Led by molecular biologist Davide Marotta, the study focused on the effects of microgravity on human brain cells, particularly neurons affected by conditions like multiple sclerosis and Parkinson's disease. The organoids were created using human stem cells from healthy donors and patients with these conditions.
The researchers prepared the organoids in specialized containers on Earth, dividing them into two groups: one remained on Earth while the other was sent to space. Upon their return, the organoids were carefully examined for differences.
Surprisingly, the organoids that traveled to space exhibited greater gene development associated with cell maturation, while the number of genes linked to cell proliferation was lower compared to those that remained on Earth. This suggests that while the organoids proliferated more slowly in space, they matured more rapidly.
Another notable finding was that the space-traveled organoids showed fewer stress-related genes and less inflammation than expected, compared to their Earth counterparts. This could be attributed to microgravity conditions being closer to the environment inside the human skull rather than the more laboratory-stressed conditions on Earth.
Loring noted, 'The unique properties of microgravity may also have effects on the human brain; there is no current in microgravity, meaning things do not move.' She added, 'I believe these organoids in space became more similar to the human brain because they are not subjected to excessive environmental influences.' This suggests they form a kind of mini-brain, or a miniature version of the human brain environment.
These findings indicate that microgravity could serve as a simulated model for more natural conditions for brain organoids compared to those studied on Earth, potentially making it an ideal environment for studying how brain cells respond to specific stimuli or drugs in conditions closer to those faced by the human brain in daily life.
Loring concluded, 'The next step we plan is to study the part of the brain most affected by Alzheimer’s disease. We also want to find out if there are differences in how neurons connect with each other in space. With these types of studies, you cannot rely on previous work to predict outcomes because there is a lack of prior research. We are in the early stages of these experiments... we are in the sky, but on the ground level of this research.'