A bed-rest study with female participants will help scientists understand changes to the immune response and decreased resistance to infection in space.
Investigators with the National Space Biomedical Research Institute (NSBRI) are researching the immune system as part of the Women's International Space Simulation for Exploration (WISE), a collaborative venture that includes NASA, the European Space Agency, the Centre National D'Études Spatiales (French Space Agency) and the Canadian Space Agency. The study is being carried out by the French Institute for Space Medicine and Physiology (MEDES) in Toulouse, France.
"It is clear from existing data that space flight conditions alter immune responses," said Dr. Gerald Sonnenfeld, a researcher on the NSBRI's Immunology, Infection and Hematology Team. "Space has such limited access; to research the immune response, we use a bed-rest model because it provides conditions similar to space conditions – fluid shift to the head and a lack of weight-bearing on the lower limbs."
Changes in immunity could have serious effects on an astronaut's ability to resist infection and the development of tumors. Possible causes for a compromised immune system include exposure to radiation and the effects of microgravity. With current expeditions to the International Space Station for extended periods and future exploration missions to the moon and Mars, astronauts will be exposed to chronic radiation that could result in serious health problems.
To help unravel the infection-resistance issue, Sonnenfeld is researching the overall impact of the body's immune response under space-like conditions. Through tests taken before, during and after bed rest, he will gauge whether participants' white blood cells divide normally and whether messengers of the immune system, called cytokines, are produced. Sonnenfeld also will study the frequency by which latent viruses are reactivated and whether participants mount an immune response to a harmless vaccine, phiX174, that is introduced during the study.
"In the past, most bed-rest studies for immunity have been carried out on men. It is significant to be part of the international WISE study because scientists and the space community want valid conclusions about effects on women," said Sonnenfeld, who is also vice president for research at Binghamton University, State University of New York.