Space travel is hard on the body. Astronauts who spend extended periods of time in orbit experience accelerated bone loss, compromised immune systems, changes in body mass and gene expression, and impaired cognition and cardiovascular functioning.
While many of the observed impacts of space travel seem to fade back on earth, researchers from far flung fields of science are still full of questions that have widespread implications for modern medicine – and for missions to Mars.
Studying how lengthy stretches in space affect our organs, systems, and genetics requires serious space-age ingenuity. Even if there was extra room on the International Space Station for human guinea pigs, sending a person into orbit is prohibitively expensive.
One solution is tissue-on-a-chip technology. Tissue chips, currently the focus of a partnership between arms of the NIH and NASA, are devices roughly the size of a cellphone that house a fluid microenvironment in which cells and tissue can grow and behave just like they would in a living organism.
In other words, tissue chips are well suited for space-based science.
With that in mind, researchers from the UW Institute for Stem Cell and Regenerative Medicine (ISCRM) are taking part in a collaborative effort to send heart tissue on chips to the International Space Station. Nate Sniadecki, PhD, Professor of Mechanical Engineering, and ISCRM faculty member is the lead investigator from the University of Washington.
On Friday March 6, heart tissue chips officially began their journey to space on a SpaceX Dragon cargo shuttle, where they will spend 30 days circling the Earth.
The Primary Investigator for the project is former ISCRM faculty member Deok-Ho Kim, PhD, now Associate Professor of Biomedical Engineering and Medicine at The Johns Hopkins University. Other primary collaborators are Dr. Peter Lee, a cardiologist from Ohio State University and staff members from Bioserve Space Technologies at the University of Colorado Boulder.
“We know that the unique conditions in space have adverse effects on cardiac functioning,” says Sniadecki. “Microgravity and radiation exposure are associated with changes in blood flow and irregular heartbeats. Our goals are to understand how to keep hearts healthy in space and to gain new insights on the mechanism at work in heart disease.”
The heart-on-a-chip mission began in the Sniadecki and Kim labs, where ISCRM researchers used induced pluripotent stem cells to grow the cardiomyocytes (or heart muscle cells) that would populate the tissue chips. The Sniadecki and Kim teams banked billions of heart cells and partnered with Bioserve Technologies to design chips that would keep the cells safe and snug in the tightly packed International Space Station.
To grow the heart cells required for the mission, Sniadecki and Kim turned to Jonathan Tsui, a postdoctoral fellow in Bioengineering. Tsui applied technologies he developed on his PhD project to differentiate stem cells into the cardiomyocytes that would became the subjects in the extraterrestrial experiment. In February, he traveled to the Kennedy Space Center to monitor the tissue samples and prepare them for their journey.
For Tsui, who self-identifies as a lifelong space geek, the experience of sending something to space and back has been mind-blowing. “One of the most rewarding aspects of the project is knowing something I’ve worked on for so long could potentially have a far-reaching impact on human spaceflight.”
It won’t be the first time human heart cells have been to space ex vivo. However, it is the first time scientists will be able to study heart cells in a 3D setup that more closely mimics the natural habitat of cardiomyocytes. All the better to track every contraction of the heart cells, which the researchers will be able to do in real-time.
The technology to measure the contractile force of the hearts cells was designed by Ty Higashi, a PhDs student in Mechanical Engineering. Higashi worked with project partners at Bioserve in Boulder, Colorado to make a flight friendly version of the circuitry system.
The heart muscle tissue is suspended between two flexible pillars. According to Higashi, The flexible pillars contain tiny magnets. When the muscle tissue contracts, the position of the embedded magnets changes, and the motion can be detected by a sensor, then relayed automatically back to Earth.
“Getting functional data back from space is exciting,” says Sniadecki. “We’re going to have real-time readings on muscle contractions. If we see arrythmias, we’ll know whether they get weaker or stronger. And all of this will tell us a lot about the effects of microgravity on heart functioning over time.”
When the tissue chips return to earth, the researchers will examine changes at the protein and gene level and track whether the changes are permanent or temporary. These insights could one day help scientists develop and test drugs to help protect against the harsh conditions of space, or even counteract aging effects for non-astronauts.
A similar experiment is already giving one of Sniadecki’s ISCRM colleagues new insights on kidney pathology and drug discovery. In 2019, Ed Kelly, PhD, Associate Professor of Pharmaceutics, was part of a research team that send kidney chips into space to study the effects of microgravity on human kidney tissue and to gather data about the onset of osteoporosis.
Sniadecki emphasizes the role the ISCRM community played in the project’s development, particularly when challenges arose. When one batch of cells became contaminated, other ISCRM labs contributed replacement cells. Shipping was another challenge. When the cells proved too fragile for UPS trucks and commercial cargo holds, a team effort involving a lot of brainstorming, and a little help from TSA, led to a fix: stowing the space-bound chips in overhead compartments.
As the heart chips circle earth 250 miles overhead, Sniadecki reflects on what it means to conduct experiments in space. “The kid in me might have dreamed about it. But I never thought my lab would do it. It feels like science fiction, but it’s not. We’re pushing science in new directions. And I can’t wait to see where it takes us.”
This space medicine research project is funded by the National Center for Advancing Translational Sciences and the National Institute of Biomedical Imaging and Bioengineering. This heart tissue study is part of the national “Tissue Chips in Space” program.
Watch video of the launch: https://www.youtube.com/watch?v=CAacLfMhUvE