Liver tissue experiments planned for the International Space Station may ultimately provide alternatives to livers for transplantation, researchers reported at the American College of Surgeons Clinical Congress in San Francisco.

Experiments completed thus far indicate that the unique conditions of low Earth orbit, within 1,200 miles from Earth, will help the liver tissues to self-assemble with enhanced functionality, compared to Earth-based methods, they said.

“This represents a critical step toward creating viable liver tissue implants that could serve as an alternative or adjunct to traditional liver transplants,” study leader Tammy Chang, MD, PhD, of the University of California, San Francisco said in a statement.

The cells in the experiments are created from normal human cells reprogrammed to act like embryonic stem cells, which means they can change into many different types of cells.

Unlike Earth-bound tissue engineering methods, microgravity allows the cells to float freely and organize naturally, resulting in more physiologically accurate tissues, the researchers explained.

They have developed a customized bioreactor, dubbed the "Tissue Orb," to house their experimental tissues, which simulates the natural blood flow process of human tissues.

The researchers are also working on advanced cooling techniques to allow for safe transport of engineered tissues from space to Earth, maintaining them below freezing without damaging them. This technology could extend the shelf life of engineered tissues and potentially be applied to whole organs, they said.

The spaceflight experiment is scheduled for launch in February 2025.