Bringing Health Tech From Space

NASA astronaut Christina Koch works inside the Life Sciences Glovebox on the International Space Station with the Kidney Cells experiment to examine how kidney health is affected by microgravity and other factors of space travel. (Photograph courtesy NASA/Nick Hague)

Public health drugs typically undergo decades of research and clinical trials to assess their efficacy in humans. Tissue chips are a type of biomedical device that can significantly shorten this timeline from years to months.

Tissue chips, also called organ-on-chip (OOC), are engineered devices containing human cells that mimic physiological conditions. These chips, developed by the National Institutes of Health’s (NIH) National Center for Advancing Translational Sciences (NCATS), are also being sent to the International Space Station U.S. National Laboratory (ISS National Lab) to study the effects of a microgravity (nearly or zero-gravity) environment on the human body.

In December 2005, the United States designated its part of the ISS as a National Laboratory, highlighting its importance for scientific research. This decision aimed to advance research missions of agencies like the National Institute of Health. National Aeronautics and Space Administration (NASA) astronauts have worked with NIH researchers to conduct experiments on the space station for more than a decade.

The development and study of technologies like tissue chips have been made possible through collaboration between the two U.S. government agencies focused on health and space.

Tissue chips in space

The U.S. Congress established the NCATS in 2012 to address inefficiencies in translating basic scientific discoveries into diagnostics, treatments and cures. Dr. Danilo Tagle, the director of the Office of Special Initiatives, started the tissue chips program.

While approximately 10,000 diseases have been identified, only 5 percent have effective treatments. “The process of translating basic discoveries, such as identifying diseases, into diagnostics, treatments and cures has been very inefficient,” Tagle explains. The tissue chips technology, he says, has been developed to improve outcome predictions by emulating human physiological responses. “The chips are miniaturized and contain human-relevant cells and tissues,” he adds.

The program has successfully developed various tissues and organs, like kidney, liver, blood-brain barrier, and muscle heart on a chip. These tissue chips have proven to capture human responses more accurately than traditional animal testing models.

Over time, scientists began exploring the use of tissue chips in areas of research that are difficult to model, like aging, explains Tagle. “This is typically studied in animal models like rats, dogs and monkeys. However, it can take years, if not decades, to wait for the animals to age,” he explains. Tagle says his study revealed that astronauts experience accelerated aging when exposed to microgravity for a long period of time—months to no more than a year. This finding led to a collaboration between NIH and NASA. Since then, NCATS has launched nine missions with about 15 payloads, including tissue chips mimicking various conditions like cardiovascular, muscle bone joint, and lungs.

The results have been promising, demonstrating that tissue chips can model aging processes quickly. The program is now expanding to study interconnected organ systems using multi-organ chips, enhancing the understanding of complex biological interactions.

Tagle explains that tissue chips allow researchers to study how human cells and tissues react in real-time, especially in unique environments like outer space. Traditionally, scientists would have to collect samples from astronauts and send them back to Earth for study. “With built-in sensors in the tissue chips, we can now actually study these reactions in real-time as they occur in space,” he explains.

NIH and NASA

In September 2007, NASA signed a memorandum of understanding with NIH for the “development of biomedical research approaches and clinical technologies for use on Earth and in space and research in Earth and space-based facilities that could improve human health on Earth and in space.” This was the first such agreement between NASA and another agency to use the ISS as a National Laboratory.

This agreement paved the way for the creation of the NIH BioMed ISS program. This program encouraged scientists to propose biomedical research that could use the ISS’s unique environment—like microgravity and radiation—to test new ideas that might benefit human health on Earth.

“NIH funded the first three applications under this program in 2010 and a fourth in 2011,” says Dr. Jonelle Drugan, deputy chief of the Scientific Planning, Policy, and Analysis branch at NIH’s National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). Astronauts on the ISS conducted experiments on three of the funded grants: Gravitational Regulation of Osteoblast Genomics and Metabolism, Osteocytes and Mechano-Transduction, and Suppression of the Immune Response in Spaceflight and Aging.

The osteocytes and mechano-transduction study, developed by Dr. Paola Divieti Pajevic of Massachusetts General Hospital, studied the cellular and molecular mechanisms that allow bone to respond to stresses, like gravity. The goal was to develop therapies that could mitigate bone loss in individuals with limited physical activity due to illness or injury.

In 2021, Dr. Pajevic published findings indicating that microgravity on board the ISS altered gene expression of osteocytes, the major mechanical sensing cells of bone. The results also showed that some commonly used ground-based simulated microgravity devices do not accurately replicate the conditions experienced in space. These findings have significant implications not only for the spaceflight program but also for understanding and treating bone loss diseases caused by reduced mechanical loading, such as those resulting from immobilization.

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