SpaceX’s Dragon cargo ship is scheduled to launch Tuesday evening (March 14) and carry nearly 6,300 pounds (2,860 kilograms) of cargo to the International Space Station (ISS). But alongside the spacewalk gear, vehicle hardware and fresh fruit for the crew, there will be several small devices containing something more unusual: beating human heart tissue.
The tissue will be used in two experiments — Cardinal Heart 2.0 and Engineered Heart Tissues-2 — that will test whether existing drugs can help prevent or reverse the adverse effects of space travel on the heart.
The research shows that Space travel can shrink the heart, because the heart muscles don’t have to work as hard to pump blood through the upper parts of the body in zero gravity. In addition, the heart can change shape under the influence of microgravity as blood moves up from the legs and abdomen into the head and torso, causing the heart to swell NASA (opens in new tab).
Studies suggest that the heart also experiences cellular changes associated with aging during spaceflight. Therefore, not only is this research crucial for future space exploration, but it could also lead to improved treatments for age-related heart dysfunction and diseases on Earth. Devin Mair (opens in new tab)a graduate student at Johns Hopkins University involved in Engineered Heart Tissues-2 said during a NASA news conference on Tuesday.
Related: Tiny “hearts” self-assemble in lab dishes and even beat like the real ones
The experiments are part of the Tissue Chips in Space initiative, a joint project between the National Institutes of Health and the International Space Station National Laboratory that aims to understand the effects of space travel and microgravity on the human body NASA (opens in new tab).
The Engineered Heart Tissue-2 (opens in new tab) The experiment involves two devices that transport cardiomyocytes — the heart muscle cells that contract — in small, fluid-filled chambers. The muscle cells were grown from stem cells and made into 3D shapes in the laboratory. They were then stretched between two posts in each chamber, much like tennis nets are hung between two posts. A post contains a magnet that moves each time the muscle cells contract. A sensor tracks the movement of the magnet, allowing researchers to monitor muscle contractions in real time.
Mair and his colleagues previously sent heart tissue into space in March 2020, and in that experiment they observed signs that the cells’ mitochondria weren’t working properly, he said at the NASA press conference. Mitochondria provide electricity to cells, driving the heart’s pumping, and their malfunctioning has been linked to a variety of heart problems, including irregular heartbeats and heart failure. In an experiment launched on that trip to the ISS, the team will continue to study mitochondrial dysfunction and test several existing drugs to see if they prevent or reverse the problems, Mair said.
“These drugs specifically target mitochondrial dysfunction and upstream mechanisms that lead to that dysfunction,” Mair told Live Science in an email.
Likewise the Cardinal Heart 2.0 (opens in new tab) The experiment will use tiny 3D clumps of heart tissue, called heart organoids, to test whether already approved drugs can protect heart cells from the stress of microgravity. The organoids will be treated prior to Dragon’s launch, with the aim of preventing the onset of the negative effects of microgravity. Dilip Thomas (opens in new tab), a postdoctoral researcher at Stanford Cardiovascular Institute involved in Cardinal Heart 2.0, said at the press conference. Those drugs include a statin and a blood pressure-lowering drug used for heart failure, Thomas told Live Science in an email.
Grown from stem cells, the organoids are tiny, full-size models of hearts that mimic key features of the organ’s structure and function. They contain cardiomyocytes, as well as cells that form a physical framework for heart muscles (cardiac fibroblasts) and those that line blood vessels (endothelial cells).
The Dragon spacecraft is scheduled for launch Tuesday at 8:30 p.m. EDT (Wednesday 0030 GMT) from NASA’s Kennedy Space Center in Florida. This is how you see it live (opens in new tab).