La station spatiale internationale ISS sert non seulement des missions spatiales, mais aussi un laboratoire pour des missions biologiques: la culture d’organes humains.
Que signifie cultiver des organes humains en apesanteur? Veuillez trouver les réponses dans l’article suivant de l’expert en cellules souches Alysson R. Muotri. Article publié sur Live Science juillet 2020.
This is why space experiences are so precious. Thanks to them, scientists have more new perspectives on biology, a better understanding of the formation of human tissues.
Gravity affects the way proteins and genes interact within the cell, creating polarized tissues, a fundamental step in the development of natural organs in humans. And that’s exactly how gravity influences cellular behavior.
When we regenerate complex three-dimensional (3D) tissue in the medical implant lab, gravity gets in the way. This becomes difficult because the bio-reactor devices when used on Earth will be subject to some inherent limitations.
Nourish human tissues and organs in the laboratory
To grow tissue in the lab, scientists use scaffolds as surfaces for cells to attach to in a predetermined fixed form. For example, a structure shaped like kidney cells would be used to grow an artificial kidney. In fact, while this strategy helps with tissue culture in the early stages, there are many long-term issues, such as immune responses to synthetic media or inaccurate structures.
In contrast, cells can comfortably organize into precision three-dimensional structures without the need for a weightless shelving foundation. Once gravity is removed from the equation, researchers like Alysson can learn new ways to nourish human tissue, such as how to grow cartilage and blood vessels in man-made environments by simulating cellular arrangements. Zero gravity conditions are an advantage even if this isn’t what happens in the uterus (since the uterus depends, after all, on gravity).
This bioculture system will help biologists understand how space affects human health by studying cells grown in microgravity on the ISS.
And that’s what’s happening on the ISS.
Based on these experiments, researchers will optimize tissues developed for use in basic science, personalized medicine, and basic transplantation.
Why should we produce human organs in space, there are other reasons
After participating in long-duration space missions, the bodies of astronauts undergo a series of physiological changes. Some of these may be reversed over time, some may not, and it will change the future of humanity’s space travel.
Not only do we get to know what bothers the internal organs of astronauts when we study their bodies before and after missions, but also a little more about the mechanisms responsible for the changes. So space-based human tissue culture complements this kind of research and points to ways to fight change.
Ultimately, all life forms that science is known to have evolved in the presence of microgravity. Without gravity our brains could have evolved in a different trajectory, for example our liver would not filter fluids like it does on Earth.
We can predict how the fetus will develop in the womb through the reproduction of human embryo formation in space. Several research initiatives are underway on miniature human brain models in Alysson’s laboratory on the ISS. Researchers designed the microcosm (miniature human brain) to know the effect on the growing human brain without gravity. These projects have profound implications for future human space achievement (can humans successfully reproduce in space?).
In addition, these studies will also improve generations of artificial organs used to test drugs and therapies on earth.
Could the best treatments for neurodevelopmental and degenerative diseases endured by millions of people around the world come from space research?
This is the question Professor Alysson asks to finish his writing.
Professor Alysson R. Muotri is Professor of Pediatrics and Molecular and Cellular Medicine at the University of California (San Diego, USA). He is a stem cell biologist with an interest in brain health and evolution. His lab is studying how the human brain forms inside the womb and how changes in the process have lifelong consequences on human behavior, such as autism and schizophrenia. Part of the lab’s work is the development of brain cells in space.
