World-first MARROW study collected breath and blood samples from astronauts to improve health outcomes of space travelers and patients here on Earth
Jeff Bezos, William Shatner, and Richard Branson may not have suffered complications from their short suborbital jaunt near the Kármán line, but they could have, had they felt the effects of zero-gravity for a longer period, according to a new Ottawa-led study that sheds some light on the impact of space travel on our health.
Dr. Guy Trudel, a rehabilitation physician and researcher at The Ottawa Hospital and professor in the faculty of Medicine at the University of Ottawa and his team just published the results of a five-year study that reveals how space travel causes lower red blood cell counts, known as space anemia.
The MARROW research project, funded by the Canadian Space Agency, was done with the help of 14 astronauts at the International Space Station - including Canadian astronaut Dr. David Saint-Jacques. Results show that their bodies destroyed 54 percent more red blood cells in space than they normally would on Earth, according to the study published in Nature Medicine.
Better understanding space anemia
“Space anemia has consistently been reported when astronauts returned to Earth since the first space missions, but we didn’t know why,” explains lead author Dr. Guy Trudel. “Our study shows that upon arriving in space, more red blood cells are destroyed, and this continues for the entire duration of the astronaut’s mission.”
Prior to this study, space anemia was thought to be a quick adaptation to fluids shifting into the astronaut’s upper body when they first arrived in space. Astronauts lose 10 percent of the liquid in their blood vessels this way. It was thought astronauts rapidly adjusted their red blood cell numbers to restore the balance, and that red blood cell control was back to normal after 10 days in space.
Instead, Dr. Trudel’s team found that enhanced red blood cell destruction was a primary effect of being in space, not just caused by fluid shifts. They demonstrated this by directly measuring red blood cell destruction markers in 14 astronauts during their six-month space missions.
On Earth, our bodies create and destroy 2 million red blood cells every second. The researchers found that astronauts were destroying 54 percent more red blood cells during the six months they were in space, or 3 million every second. These results were the same for both female and male astronauts.
Having fewer red blood cells in space isn’t a problem when your body is weightless, but when landing on earth and potentially on other planets or moons, anemia affecting your energy, endurance, and strength can threaten mission objectives. - Dr. Trudel
Dr. Trudel’s team made this discovery thanks to techniques and methods they developed to accurately measure red blood cell destruction. These methods were then adapted to collect samples aboard the International Space Station. In Dr. Trudel's lab at the University of Ottawa, they were able to precisely measure the tiny amounts of carbon monoxide in the breath samples from astronauts. One molecule of carbon monoxide is produced every time one molecule of heme, the deep-red pigment in red blood cells, is destroyed.
While the team did not measure red blood cell production directly, they assumed the astronauts generated extra red blood cells to compensate for the cells they destroyed. Otherwise, the astronauts would end up with severe anemia, and would have had major health problems in space.
“Thankfully, having fewer red blood cells in space isn’t a problem when your body is weightless,” said Dr. Trudel. “But when landing on Earth and potentially on other planets or moons, anemia affecting your energy, endurance, and strength can threaten mission objectives. The effects of anemia are felt once you land and must deal with gravity again.”
In this study, five out of 13 astronauts were clinically anemic when they landed —one of the 14 astronauts did not have blood drawn on landing. The researchers saw that space-related anemia was reversible, with red blood cells levels progressively returning to normal three to four months after returning to Earth.
Interestingly, the team repeated the same measurements one year after the astronauts returned to Earth and found that red blood cell destruction was still 30 percent above preflight levels. These results suggest that structural changes may have happened to the astronaut while they were in space that changed red blood cell control for up to a year after long duration space missions.
The discovery that space travel increases red blood cell destruction has several implications, it:
- highlights the need to screen astronauts and space tourists for existing blood or health conditions that are affected by anemia.
- impacts longer missions to the Moon and Mars, as per a recent study by Dr. Trudel’s team which found that the longer the space mission, the worse the anemia gets.
- will require an adapted diet for astronauts.
- informs us that it is unclear how long the body can maintain this higher rate of destruction and production of red blood cells.
The low gravity in space weakens muscles and bones. The same happens to patients who spend a long time in bed. MARROW's findings will be used to help ease the effects of physical inactivity on seniors, those with reduced mobility or undergoing rehabilitative treatment, and bedridden patients. - Dr. Trudel
Findings could be applied on Earth
As a rehabilitation physician, most of Dr. Trudel’s patients are anemic after being very ill for a long time with limited mobility, and anemia hinders their ability to exercise and recover. Bedrest has been shown to cause anemia, but how it does this is unknown. Dr. Trudel thinks the mechanism may be like space anemia. His team will investigate this hypothesis during future bedrest studies done on Earth.
“These findings are spectacular, considering these measurements had never been made before and we had no idea if we were going to find anything. We were surprised and rewarded for our curiosity. If we can find out exactly what’s causing this red blood cell destruction, then there is a potential to treat it or prevent it, both for astronauts and for patients here on Earth,” concluded Dr. Trudel.
MARROW's findings will also be used to help ease the effects of physical inactivity on seniors, those with reduced mobility or undergoing rehabilitative treatment, and bedridden patients.
For more information about the MARROW project, read this story about Canadian Space Agency astronaut Dr. David Saint-Jacques’ participation in the study, and this article in the University of Ottawa’s Tabaret.
This study was funded by the Canadian Space Agency. The Ottawa Hospital Research Institute and the University of Ottawa Faculty of Medicine are also supported this research through the Blueprint Translational Research Group’s Excelerator program.
Hemolysis contributes to anemia during long-duration space flight by Guy Trudel, Nibras Shahin, Timothy Ramsay, Odette Laneuville, Hakim Louati, was published in Nature Medicine on January 14, 2022.
Media contacts:
Amelia Buchanan
Ottawa Hospital Research Institute
[email protected]
Paul Logothetis
University of Ottawa
[email protected]
Isabelle Mailloux
University of Ottawa
[email protected]
