Experiment on final flight of Discovery probes effects of spaceflight on immune response
GALVESTON, Texas — The space shuttle Discovery’s landing next week will bring to an end the 27-year career of NASA’s oldest operational spacecraft. It will also mark the end of 30 years of space shuttle involvement in a research effort that could be crucial to further human exploration of outer space: the study of why spaceflight makes people more vulnerable to attack by viruses and bacteria.
Sixteen mice now floating in two self-contained modules on Discovery’s mid-deck are at the center of the final shuttle-based immunology experiment, a detailed investigation into the effects of spaceflight on infection by a common respiratory virus. The mouse experiment is a collaboration between teams from the University of Texas Medical Branch at Galveston and NASA’s Ames Research Center at Moffett Field, California.
“Since the Apollo missions, we have had evidence that astronauts have increased susceptibility to infections during flight and immediately post-flight — they seem more vulnerable to cold and flu viruses and urinary tract infections, and viruses like Epstein-Barr, which infect most people and then remain dormant, can reactivate under the stress of spaceflight,” said Dr. Roberto Garofalo, a professor at UTMB Health and principal investigator for the project. “We want to discover what triggers this increased susceptibility to infection, with the goal both of protecting the astronauts themselves and people with more vulnerable immune systems here on Earth, such as the elderly and young children.”
The mice aboard Discovery will be in orbit for 12 days, during which time shuttle astronauts will perform daily checks on their health and well-being. Within two hours of the shuttle’s return to Earth, eight of the animals will be infected with respiratory syncytial virus — a pathogen that infects almost all human children by age two and ordinarily causes a relatively harmless cold-like upper respiratory disease. In some children, however, the infection spreads to the lungs, where the inflammation it generates causes coughing, wheezing and extreme difficulty in breathing.
Another group of mice kept in nearly identical conditions on the ground will also be exposed to the virus. Garofalo’s team will conduct genetic and protein studies of the lung and nasal tissues of both sets of mice, evaluating lung inflammation, viral replication and other key factors related to RSV infection in mice.
“We have substantial experience using mice to study immune response to RSV infection, and that will enable us to look at all the aspects of the immune responses of these mice as well as the pathological manifestations of the disease, looking at ways in which the space environment affects this respiratory infection,” Garofalo said.
Understanding how spaceflight impairs the immune system and finding ways to make sure that infection doesn’t threaten the health of space travelers are expected to become increasingly important in the future, as NASA plans human expeditions beyond the relative safety of Earth orbit — to Mars, for example, or an asteroid. The developing commercial spaceflight industry, which hopes to launch large numbers of private citizens into orbit in the near future, also has a stake in ensuring that its passengers stay safe and healthy.
Despite the shuttle program’s imminent end, Garofalo said, immune system experiments in space may well continue on the International Space Station.
“The space environment incorporates many factors that we know affect the immune system — microgravity, radiation, even different nutritional standards — all acting in a relatively short period of time,” Garofalo said. “The space station provides a unique environment for generating answers to fundamental questions about the human immune system. Those answers will benefit people here on Earth, and there’s been a lot of interest in pursuing them.”
Images of the special animal enclosure modules and astronauts examining mice on a previous flight are available upon request.
ABOUT UTMB Health: Established in 1891, Texas' first academic health center comprises four health sciences schools, three institutes for advanced study, a research enterprise that includes one of only two national laboratories dedicated to the safe study of infectious threats to human health, and a health system offering a full range of primary and specialized medical services throughout Galveston County and the Texas Gulf Coast region. UTMB Health is a component of the University of Texas System.