Low gravity in space travel found to weaken and disrupt normal rhythm in heart muscle cells | Science & Technology

The scientists said the heart tissues “really don’t fare well in space,” and over time, the tissues aboard the space station beat about half as strong as tissues from the same source kept on Earth.

The findings, they say, expand scientists’ knowledge of low gravity’s potential effects on astronauts’ survival and health during long space missions, and they may serve as models for studying heart muscle aging and therapeutics on Earth.

A report of the scientists’ analysis of the tissues will be published during the week of Sept. 23 in the Proceedings of the National Academy of Sciences.

Previous studies showed that some astronauts return to Earth from outer space with age-related conditions, including reduced heart muscle function and arrythmias (irregular heartbeats), and that some, but not all, effects dissipate over time after their return.

But scientists have sought ways to study such effects at a cellular and molecular level in a bid to find ways to keep astronauts safe during long spaceflights, says Deok-Ho Kim, Ph.D., a professor of biomedical engineering and medicine at the Johns Hopkins University School of Medicine. Kim led the project to send heart tissue to the space station.

To create the cardiac payload, scientist Jonathan Tsui, Ph.D., coaxed human induced pluripotent stem cells (iPSCs) to develop into heart muscle cells (cardiomyocytes). Tsui, who was a Ph.D. student in Kim’s lab at the University of Washington, accompanied Kim as a postdoctoral fellow when Kim moved to The Johns Hopkins University in 2019. They continued the space biology research at Johns Hopkins.

Tsui then placed the tissues in a bioengineered, miniaturized…