Astronauts have a much higher incidence of infections in comparison to humans living under normal gravity. Dr. Millie Hughes-Fulford from the molecular biology department of University of California San Francisco is trying to figure out what may cause this difference. As part of her experiments she has been studying the stem cells that give rise to blood and immune system cells, called hematopoietic stem cells. Today, Dr. Hughes-Fulford is expecting to receive 16 mice that were flown on the Space Shuttle Discovery for two weeks. Various aspects of the stem cells and the immune system will be studied.
The importance of understanding zero-gravity associated immune deficiency comes from the aim of establishing long-term space missions to places like mars, in which the current immune deficiencies observed may take a larger toll on the astronauts. Dr. Hughes-Fulford stated that "many of the conditions found in astronauts are similar to muscular-skeletal diseases in
paralyzed or comatose patients on Earth" she continued to state that she has seen young astronauts come down with shingles, which commonly occur in people past the age of 60.
Over the years I’ve been able to do several experiments on the shuttle, Hughes-Fulford said. We’ve found that the immune system is
suppressed when it doesn’t have gravity.
In the previous George W. Bush administration, after the Space Shuttle Columbia disintegrated on re-entry in 2003, the work on stem cells and space travel lost funding. Hughes-Fulford, Almeida, and other U.S. scientists were able to get access to space-bound missions only because of personal and institutional partnerships, however NIH funding was not permitted despite the adult stem cell nature of the experiments. Hughes-Fulford hopes the Obama administration will make it easier to conduct such spaceflight experiments. This time, Dr. Hughes-Fulford was able to send 16 mice in climate-controlled containers along with Discovery. Her team will analyze how mouse white blood cells respond to a simulated infection during flight and upon return, and compare that with how white blood cells behave in 16 Earthbound mice.
Her results from previous flight experiments are pretty compelling, said Daniel Bikle, professor of medicine and dermatology at UC San Francisco. He continued If there’s any failure of these stem cells to differentiate into normal tissues, that could cause problems, he said. If we ever do get around to sending somebody to Mars and somebody gets pregnant, if stem cells fail to differentiate you wouldn’t get a normal baby.
