Researchers at Penn State Hershey Orthopaedics and Rehabilitation, Division of Musculoskeletal Sciences, participated in a collaborative research effort to understand the effects of microgravity on the human body when on July 8, a group of mice was launched on the Space Shuttle Atlantis. The researchers, led by Henry J. Donahue, Ph.D., the Michael and Myrtle Baker Professor of Orthopaedics and Rehabilitation, plan to examine the effects of microgravity on the ability of adult bone marrow stem cells to differentiate into bone-forming osteoblasts. “The data we gain from the space shuttle experiment will help to advance our understanding of bone loss that occurs with aging or with prolonged periods of bed rest,” said Donahue. Our bones are continually being remodeled, reflecting competing processes of bone formation by osteoblasts, and bone resorption by osteoclasts.
In the near weightless environment of space, astronauts lose bone about ten times faster than a post-menopausal woman would here on Earth. It is not yet fully understood how the development of bone cells from stem cell precursors is affected by spaceflight, or what role this plays in the characteristic suppression of bone formation observed following spaceflight.
M.D./Ph.D. student Shane A.J. Lloyd, along with researchers from Harvard, University of Colorado, and University of North Carolina, worked at NASA’s Space Life Sciences Lab at the Kennedy Space Center in Florida in preparation for the flight and following the space shuttle landing. Upon return of Atlantis, Lloyd harvested bone marrow from both spaceflight and ground control mice and is now working to isolate adult stem cells from the marrow and culture these cells back at the Division of Musculoskeletal Sciences laboratory in Hershey.
The researchers will examine the rate of stem cell differentiation into bone-forming osteoblasts based on RT-PCR and western blot analyses of type 1 collagen, osteopontin, and osteocalcin expression, as well as enzyme assays of alkaline phosphatase activity, all of which reflect osteoblastic differentiation. They will also determine the rate at which the cell cultures form mineralized tissue. Results will be compared between spaceflight and control groups. Donahue notes that, “As we have become better at treating ailments like cancer and heart disease, people are now living longer. Problems from age-related bone loss [like fractures and vertebral collapse] are becoming more common and need to be addressed. A better understanding of microgravity-induced bone loss will help us better understand age-related bone loss.” The project, funded by the Michael and Myrtle Baker Orthopaedic Research Endowment, is part of the larger research program in Donahue’s laboratory, funded by the National Institutes of Health and Department of Defense. Donahue’s work explores how mechanical and molecular signals, such as those from exercise, affect bone formation and bone loss and how these processes may change with aging, particularly in post-menopausal women.
Henry J. Donahue, Ph.D.
Michael and Myrtle Baker Professor of Orthopaedics and Rehabilitation
- Graduate Study: Ph.D., biological sciences, University of California, Santa Barbara
- Postdoctoral Studies: Mayo Clinic, Rochester, Minnesota