An experiment conducted by Harrison’s group recently completed a 12-day trip through space in order to study the effects of zero gravity on bone loss. In the absence of gravity, bone mass begins to drop. Astronauts, in particular, suffer from this accelerated bone loss when they are in space. “What astronauts experience is a severe form of osteoporosis,” Harrison said. “They lose two per cent of their bone a month.”
The experiment was launched into Earth’s orbit September 14 from Baikonour, Russia aboard unmanned satellite Foton M3. The study will give insight into disuse osteoporosis, a form of osteoporosis that occurs when there is prolonged lack of pressure on the bones. A normal person is able to avoid disuse osteoporosis by moving, but bedridden patients, being unable to apply weight to their bones, are at risk. In space, where there is little or no gravity, disuse osteoporosis presents a threat to astronauts.
Harrison’s experiment focuses on the balance between two types of bone cells: the “bone-eaters” or osteoclasts, and the “bone-makers” or osteoblasts. It is currently unclear whether bone loss is caused by rapid osteoclast consumption, or osteoblasts slowing down their bone production. To tackle this mystery, Harrison’s team sent cultures of pure osteoclasts and pure osteoblasts into space, and have been analyzing the cells since their return to Earth. There have been past studies in which whole animals were sent into space, but unlike Harrison’s experiment, those studies only confirmed that bone loss occurs in zero gravity, not what is responsible—osteoclasts or osteoblasts.
The study is part of a joint venture between the Canadian Space Agency and the European Space Agency. Harrison was one of only three Canadian scientists selected after the CSA made an open call for research proposals. “It was an experience that I wouldn’t have gotten doing just your typical basic research,” said Harrison to the Varsity.
For the experiment, bone cells were grown inside bioreactors fitted onto a custom-designed, fully automated “mini-laboratory” called eOSTEO. During the trip, the cells were continuously fed a nutrient-rich medium through automatically controlled syringes. Meanwhile, growth conditions were carefully monitored and relayed by satellite every 90 seconds to ground stations in Sweden and Canada. Near the end of the trip, a fixative was added into the bioreactors, preparing them for analysis on Earth. Presently, Harrison and her group are carefully examining the cells, and are anticipating preliminary results in about a month.
