Astronaut Thomas Pesquet inserts blood samples for MARROW into the Minus Eighty-Degree Laboratory Freezer aboard the ISS. Credit: NASA
Key points:
- Astronauts experience “space anemia,” where their bodies destroy 54 percent more blood cells than normal during space travel.
- Stored fat in bone marrow helps astronauts regain red blood cells and bone.
- Understanding the body’s ability to harness energy from bone marrow fat may help treat and prevent anemia and other diseases on Earth.
Astronauts can experience “space anemia” as their bodies destroy 54 percent more blood cells than normal during space travel. A new study, published in Nature Communications, found that space travel depletes red blood cells and bone, but stored fat in bone marrow can replenish them.
Researchers examined MRI scans of 14 astronauts’ bone marrow at several time points before and after a six-month mission at the International Space Station. One month after returning to Earth, astronauts had a 4.2 percent decrease in bone marrow fat. There was a gradual return to normal levels associated with increased production of red blood cells and rebuilding of bone.
“We found that astronauts had significantly less fat in their bone marrow about a month after returning to Earth,” explained the study’s author Guy Trudel. “We think the body is using this fat to help replace red blood cells and rebuild bone that has been lost during space travel.”
The study revealed that not all astronauts had the same recovery following space travel. For example, younger astronauts had an increased ability to harness energy from bone marrow fat. Additionally, female astronauts’ bone marrow fat increased more than expected after a year.
Anemia is not a problem in space, but upon returning to Earth or other planets and moons with gravity, it can affect energy, endurance, and strength. In the clinical setting, patients that are anemic often have limited mobility that leads to lost muscle and bone mass.
The study’s results point to a mechanism for preventing and treating anemia that could help people recover from immobility on Earth and in space. This research may also provide insight into diseases associated with increases in bone marrow fat including osteoporosis, metabolic syndrome, aging, and cancer.
“Since red blood cells are made in the bone marrow, it makes sense that the body would use up the local bone marrow fat as a source of energy to fuel red blood cell and bone production,” said Trudel. “We look forward to investigating this further in various clinical conditions on Earth.”