Anemia in astronauts could be a challenge for space missions
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[January 15, 2022]
By Harikrishnan Nair
(Reuters) - The next "giant leap" for
humans may be a trip to Mars, but having enough oxygen-carrying red
blood cells for the journey might present a challenge, new research
suggests.
Even space tourists lining up for short trips might have to stay home if
they are at risk for anemia, or red blood cell deficiency, researchers
said.
Astronauts are known to experience "space anemia" but until now it was
thought to be temporary. One NASA study called it "a 15-day ailment."
Doctors attributed it to destruction of red blood cells, or hemolysis,
resulting from fluid shifts as astronauts' bodies accommodated to
weightlessness and again as they re-accommodated to gravity.
In fact, anemia is "a primary effect of going to space," said Dr. Guy
Trudel of the University of Ottawa, who led a study of 14 astronauts
funded by the Canadian Space Agency. "As long as you are in space, you
are destroying more blood cells" than you are making."
Normally, the body destroys and replaces nearly 2 million red blood
cells per second. Trudel's team found astronauts' bodies destroyed 3
million red blood cells per second during their six-month missions.
"We thought we knew about space anemia, and we did not," Trudel said.
The astronauts generated extra red cells to compensate for the destroyed
ones. But, Trudel asked, how long can the body constantly produce 50%
more red cells? A roundtrip mission to Mars would take about two years,
NASA estimated.
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David Saint-Jacques collects breath, ambient air, and blood samples
aboard the International Space Station in this undated handout photo
obtained by Reuters on January 14, 2022. NASA Anne McClain/Handout
via REUTERS
"If you are on your way to Mars and
... you can't keep up" with the need to produce all those extra red
blood cells, "you could be in serious trouble," Trudel said.
Having fewer red blood cells in space is not a problem when your
body is weightless, he added. But after landing on Earth, and
potentially on other planets, anemia could affect astronauts'
energy, endurance and strength.
A year after returning to Earth, the astronauts' red blood cells had
not completely returned to pre-flight levels, his team reported on
Friday in Nature Medicine.
Trudel also studies the effects of immobility on patients who are
bedridden for weeks or months.
The new findings mimic what he sees in his patients, he said, which
suggests that what happens in space may also be happening in
immobile patients.
"A solution to one could also apply to the other," he said.
Sulekha Anand, who researches human physiology at San Jose State
University and was not involved in the study, agreed.
"The findings have implications for understanding the physiological
consequences of space flight and anemia in patients on the ground,"
she said.
Trudel's team is studying ways to solve the problem, he said.
(Reporting by Harikrishnan Nair; Editing by Nancy Lapid and Richard
Chang)
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