At little after 3:30 p.m. EDT on April 7, 2020, the SpaceX Dragon spacecraft splashed down in the Pacific Ocean, returning to Earth after nearly a month attached to the International Space Station (ISS). The spacecraft brought back a number of physical and life sciences research projects, including heart and gut tissue chip projects that traveled to the ISS as part of the Tissue Chips in Space initiative.
The initiative is an ambitious collaborative endeavor that brings the National Center for Advancing Translational Sciences (NCATS), the National Institute of Biomedical Imaging and Bioengineering (NIBIB) and the ISS U.S. National Laboratory together to rapidly advance tissue chip technology for biomedical research.
The chips contain miniature models of living tissues built from human cells. Because tissue chips accurately model the structure and function of human organs and systems, researchers could use them to predict — more quickly and effectively than current methods allow — whether a candidate drug, vaccine or biologic agent is safe or toxic in humans. Tissue chips also can provide new opportunities for researchers to study biological processes in the extreme environment of microgravity aboard the ISS.
Prolonged exposure to microgravity — as is experienced by the astronauts on the ISS — is known to cause changes to many aspects of the functioning of the human body, including in the heart and cardiovascular system. Many of the changes caused by microgravity look similar to those caused by accelerated disease and aging processes. Using tissue chips on the ISS provides a unique opportunity for researchers to model and study conditions related to diseases and aging over weeks or months, rather than the years that it would take for these conditions to develop on Earth.
A research team led by Deok-Ho Kim, Ph.D., at Johns Hopkins University and comprising researchers from several academic institutions and other organizations developed heart tissue chips to study the structural and functional changes to the tissue caused by spending time in low gravity. The team also developed related technology needed to send the tissue chips safely into space, survive on board the ISS for nearly a month and return to Earth. The researchers hypothesized that during that period of time the tissues would undergo functional, visible and molecular changes that are similar to those that occur with illness or old age on Earth.
To create the heart tissue chips, the researchers coaxed human induced pluripotent stem cells, which have the potential to become almost any type of cell in the body, to form cardiomyocytes (heart muscle cells) that developed into small 3-D structures between two posts on a silicon scaffold. One of the posts, which was flexible and bent each time the tissue contracted, contained a small magnet. While on the ISS, the magnet’s movements were picked up by a sensor and transmitted to the researchers on the ground so they could collect data on the strength of the contractions—and any changes to that strength—remotely.
Now that the tissue chips have returned to Earth, the researchers will continue to analyze the data they collected while the tissue chips were on the ISS and compare them to data from a set of comparison chips that remained on Earth. The research team also will begin to assess the visible and molecular changes the tissue may have undergone as a result of spending time in microgravity.
On a future flight, the researchers will test methods to improve heart cell contractions, including mechanical stimulation, which mimics muscle conditioning, as well as drugs known to protect the heart from an irregular heartbeat or heart disease. Findings from the project may have implications both for improving the health of astronauts and for finding new ways to study and treat heart diseases related to aging on Earth.
For more photos, go to coverage by NCATS here.
This work was funded with support from NIBIB and NCATS (UG3 EB028094).