Stem cells grown in space show promise for accelerating biotherapies

Stem cells grown in microgravity on the International Space Station (ISS) have unique properties that could one day help accelerate new biotherapies and treat complex diseases, two Mayo Clinic researchers say. The analysis of the research by Fay Abdul Ghani and Abba Zubair, MD, Ph.D., published in NPJ Microgravityfinds that microgravity can enhance the regenerative potential of cells. Dr. Zubair is a laboratory medicine specialist and medical director of the Center for Regenerative Biotherapeutics at the Mayo Clinic in Florida. Abdul Ghani is a Mayo Clinic research technologist. Microgravity is weightlessness or almost zero gravity.

Studying stem cells in space has revealed cellular mechanisms that would otherwise be undetectable or unknown in the presence of normal gravity. This discovery shows a broader scientific value for this research, including potential clinical applications.”

Abba Zubair, MD, Ph.D., researcher, Mayo Clinic

Dr. Zubair has started stem cell experiments from his lab on three different missions to the ISS. His review provides data on the scientific question, “Is space the ideal environment for growing large numbers of stem cells?” Another key concern is whether cells grown in space could retain their strength and function after falling to Earth.

“The goal of almost all spaceflights in which stem cells are studied is to enhance the development of large quantities of safe and high-quality clinical-grade stem cells with minimal cellular differentiation,” says Dr. Zubair. “Our hope is to study these cells growing in space to improve treatment for age-related conditions such as stroke, dementia, neurodegenerative diseases and cancer.”

The challenges of developing stem cells on Earth

Adult stem cells found in bone marrow and adipose (adipose) tissue do not divide and differentiate into specialized cells. As a result, the number of adult stem cells in each patient is limited. To obtain enough stem cells for clinical research or patient use, the cells must be multiplied and expanded. It is an expensive, time-consuming process with inconsistent results.

Through research on the International Space Station, scientists have gained a new understanding of how cells multiply, function and transform into specialized cells. Importantly, they also discovered that microgravity promotes better cell growth and function compared to those grown in a laboratory on Earth.

“The space environment offers an advantage to the development of stem cells by providing a more natural three-dimensional condition for their expansion, which is very similar to the growth of cells in the human body. This is compared to the two-dimensional culture environment available on Earth which is less likely to mimic human tissue,” says Dr Zubair.

Discoveries from stem cells grown in space

The immediate value of interstellar stem cell research may be in developing tissue for disease modeling. Stem cells grown in space could be used to recreate realistic models of cancer and other diseases in a Petri dish. Researchers can then use these models to track disease progression and test new treatments to stop it.

A comprehensive review of papers from the Mayo Clinic and other academic health centers shows that space research has applications far beyond the laboratory. Several microgravity-grown stem cell lines have shown clinical potential:

• Mesenchymal stem cells are adult stem cells that secrete growth factors with healing potential. Dr. Zubair’s team has documented that mesenchymal stem cells expanded in microgravity have greater immunosuppressive abilities than those grown on Earth.
• Hematopoietic stem cells they have regenerative blood abilities to fight infection, stop bleeding, and carry oxygen. Hematopoietic stem cells grown on the ISS have shown the ability to expand and differentiate into red or white blood cells that could one day be used to manage blood cancer patients.
• Cardiovascular progenitor cells they provide the building blocks for blood vessels and heart muscle. They play a key role in muscle recovery. Growing cardiovascular progenitor cells in space could someday offer new options for repairing tissue damaged by a heart attack.
• Neural stem cells they are found in the central nervous system and play a key role in the development, maintenance and repair of the brain. Nerve cells expanded in a zero-gravity environment and retained their regenerative abilities on Earth. Researchers are studying whether nerve cells grown in space could provide replacement therapy for central nervous system diseases.

Barriers to treatment

Despite the promise of alien stem cell research, researchers face many challenges. Cells could lose their strength and ability to function after long-term exposure to microgravity. Over time, space radiation could damage DNA and affect cell growth. Another concern is whether cells growing in microgravity could become cancerous. Dr. Zubair’s team, however, found no evidence of chromosomal damage that could cause cancer in mesenchymal stem cells cultured in space.

Stem cell research in the world is in its early stages, and the full effects of cell proliferation in weightlessness are not fully understood. More scientific data, research and funding are needed to help researchers fully understand the clinical potential of space-expanded cells.

“The space research that has been done so far is just a starting point. A broader perspective on stem cell applications is possible as research continues to explore the use of space to advance regenerative medicine,” writes Dr. Zubair.

The National Aeronautics and Space Administration and the Mayo Clinic Center for Regenerative Biotherapeutics provided funding for this research.