Figure 1: Astronaut Peggy Whitson adjusts a microscope used to observe the growth of MSCs aboard the International Space Station’s laboratory module.
Source Credit: NASA (LINK)
Modern medical research has surpassed the domains of Earth to space, and for good reason. The conditions in space allow scientific experimentation without the influence of gravity, making certain types of research more accessible and effective. More specifically, experiments aboard the International Space Station (ISS) since its launch in 1998 have provided new, impactful insight into human health here on Earth. In particular, stem cell research has been an integral part of the ISS’s mission, and researchers believe that a breakthrough is close.
In 2017, Abba C. Zubair, the Director of Transfusion Medicine and Stem Cell Therapy at the Mayo Clinic collaborated with NASA to explore the growth of human-derived mesenchymal stem cells (MSCs) in an ISS laboratory. Their goal was to verify the “feasibility, potency, and safety” (Nature) of space-grown stem cells for clinical procedures both on Earth and in long-term spaceflight. MSCs are valuable due to their importance in tissue repair and regeneration as it is able to differentiate into a variety of cells, including osteocytes (cells found in bone), chondrocytes (cells found in cartilage), and adipocytes (cells found in connective tissue within the skin). Moreover, another crucial function of MSCs is their ability to release cytokines and other growth factors that catalyze the production of other stem cells such as neural, skeletal, and hematopoietic stem cells, which regenerate blood cells.
The research done by Zubair is significant as it tests the growth of stem cells in microgravity. Stem cell research on Earth faces limitations as the regular, two-dimensional cell culture does not accurately simulate the environment of human bodies in which stem cells typically develop. While cells in this setting can grow outwards, they are unable to grow upwards or downwards. Furthermore, it can also be observed that these cells are constantly in contact with the plastic or glass that contains them during experiments, thereby making them only able to organize themselves into simple, single-layered structures. Conditions on the ISS, on the other hand, eliminate these constraints, and stem cells are able to grow in three dimensions, forming complex aggregates.
The results of the investigation, which were published in June 2020, concluded with the final findings of the experiment. Microgravity not only promoted MSC secretion of cytokines and growth factors but also found that the stem cells grown in space were more immunosuppressive than their Earth counterparts. All in all, they determined that MSCs grown in space can safely have clinical applications.
The result of the experiment has several critical implications in both the scientific fields of space exploration and medicine. Further research of stem cells in space could improve the safety of astronauts in long-term space missions. Astronauts in the ISS are subject to an average of ten times more cosmic radiation than people on Earth. The environment in space can have negative effects on human health, just as it did for NASA astronaut, Scott Kelly. After spending a year on the ISS, his body was met with a number of repercussions: fluid-swollen upper body and head, unusual gene activation, an overactive immune system, inflammation in his microbiomes, and even a loss of cognitive ability. If space agencies like NASA intend to follow through with their ambitions requiring long-term spaceflight and even moon colonization, they will have to keep the health of every crew member a priority. As such, the ability to readily treat astronauts through regenerative therapy utilizing stem cells will be essential to further space exploration.
In a global population that continues to grow older, age-induced conditions like stroke, cancer, and dementia are affecting a growing number of people. As organ transplant procedures are the most effective remedy, the necessity for organ donors is proportionately rising. However, the demand for such organs is much too overwhelming relative to the limited supply. Moreover, organ transplants through donors face the risk of rejection, as the human body only accepts compatible organs. Fortunately, further research on stem cells will allow doctors to close this gap. The ability to grow tissues and entire organs in space could allow patients’ own cells to be used, lowering the possibility of rejection. Stem cells will, without question, prove themselves to be a critical component of tissue engineering.
If it were not for the laboratories available in microgravity conditions, stem cell research would have reached a roadblock long ago. The laboratories in Earth’s orbit provide a new medium for scientists to test the limits of medical research, and to apply their findings back on Earth’s surface. Within these experiments, stem cell research, in particular, will undoubtedly continue to be a major point of focus for scientists and astronomers alike to make the next breakthrough discoveries in their proper fields.
Q&A:
Sally: Is there a way to imitate outer space condition?
While it is possible to emulate microgravity here on Earth, it is only in short periods of time. The ISS allows longer durations of experiments to observe long term effects of microgravity.
Jiwon: Why is the ability of MSCs to release growth factors that catalyze the production of other stem cells important? What will happen to a human body without enough of these MSCs?
Found in the bone marrow, MSCs are stem cells that are imperative to both the production and maintenance of skeletal tissue. These specific kind of stem cells are also important as they are multipotent, meaning they can differentiate into many different types of cells.
Josh: What are some current limitations in advancing stem cell research in space?
One obstacle in this effort will definitely be a time constraint, as the ISS is planning to close by the year 2024. The eventual shutdown of the ISS will be a big blow to a large range of sciences as its laboratory in microgravity has provided many breakthroughs in its twenty years of orbit.
John: Do the potential health benefits justify the economic resources required to sustain this process?
There is definitely a good reason to invest large sums of money into this research. It has benefits that can be realized both within Earth as well as in outer space, such as the growth of human tissues in space.
Works Cited:
“Cutting-Edge Biomanufacturing Aboard the International Space Station.” NASA, NASA, science.nasa.gov/science-news/news-articles/3d-biomanufacturing-aboard-the-ISS.
Huang, P., Russell, A.L., Lefavor, R. et al. Feasibility, potency, and safety of growing human mesenchymal stem cells in space for clinical application. npj Microgravity 6, 16 (2020). https://doi.org/10.1038/s41526-020-0106-z
Johnson, Michael. “20 Breakthroughs from 20 Years of Science Aboard the ISS.” NASA, NASA, 26 Oct. 2020, www.nasa.gov/mission_pages/station/research/news/iss-20-years-20-breakthroughs.
“Microgravity Tissue Engineering Could Help Deep Space Crews Regrow Human Body Parts.” Thomasnet® - Product Sourcing and Supplier Discovery Platform - Find North American Manufacturers, Suppliers and Industrial Companies, Thomasnet, www.thomasnet.com/insights/microgravity-tissue-engineering-could-help-deep-space-crews-regrow-human-body-parts/.
“Studying Stem Cells in Space for the Benefit of Humankind on Earth and Beyond.” ISS US National Laboratory, 11 June 2020, www.issnationallab.org/blog/stem-cell-research-results-published-zubair/#:~:text=The%20investigation%20established%20the%20feasibility,to%20survive%20better%20in%20microgravity.
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