(Reuters) – The next “giant leap” for humans could be an expedition to Mars, but the availability of oxygen-carrying red blood cells for the journey might present some challenges new research suggests.
Researchers said that even space tourists who are waiting to travel for short periods might need to stay home if they are at high risk of developing anemia or red blood cell deficiencies.
Although “space anemia” is a regular occurrence in astronauts, it was thought that it was temporary. One NASA study classified it as “a 15-day illness.”
Doctors attributed it to destruction of red blood cells or hemolysis, that resulted from fluid shifts that occurred as astronauts’ bodies adjusted to weightlessness, and then again when they re-acclimatized to gravity.
In reality, anemia is “a main effect of going to space,” said Dr. Guy Trudel of the University of Ottawa who was the lead researcher in a study of 14 astronauts funded by the Canadian Space Agency. “As long as you’re in space, you’re losing more blood cells than you’re creating.”
Normally the body replaces and destroys around 2 million red blood cells each second. Trudel’s team discovered that astronauts destroyed 3 million red blood cell per second during their six-month missions.
“We thought we knew about space anemia, but we didn’t,” Trudel said.
The astronauts generated extra red cells in order to compensate for the ones destroyed. 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.
Trudel stated that “if you’re on the way to Mars but… you can’t keep up” the need to produce all the red blood cells, “you could get into serious trouble.”
He said that having fewer red blood cells in space is not a problem if your body is weightless. But once you land on Earth, and potentially on other planets, anemia can affect astronauts’ energylevels, endurance and strength.
One year after returning Earth astronauts’ red blood cells have not fully returned to pre-flight levels the team reported on Friday in Nature Medicine.
Trudel also studies the effects of immobility on patients who are sick for a few weeks or even months.
The new findings mimic what he observes in his patients, he explained, which suggests that what occurs in space may also be happening to patients who aren’t mobile.
He added, “A solution to one problem could also be applied to another.”
Sulekha Anand, a researcher at San Jose State University in human physiology, has agreed to the study.
“The findings have implications for understanding the physiological effects of space flight and anemia in patients who are on the ground,” she said.
Trudel said that Trudel’s team is looking for ways to address the issue.
SOURCE: https://go.nature.com/33G3ceU Nature Medicine, online January 14, 2022.
