'Bone marrow fat may replenish depleted red blood cells, rebuild bone'

TORONTO: A study of 14 astronauts suggests that while space travel depletes red blood cells and bone, the body can eventually replenish them back on Earth with the help of fat stored in the bone marrow, a find that could improve health in space as well as on Earth.

The study, published in the journal Nature Communications, has important implications for health in space and on Earth.

“We found that astronauts had significantly less fat in their bone marrow about a month after returning to Earth,” said senior study author Dr Guy Trudel, a rehabilitation physician and researcher at The Ottawa Hospital and professor at the University of Ottawa.

“We think the body is using this fat to help replace red blood cells and rebuild bone that has been lost during space travel,” Trudel added.

The new study involved MRI scans of the astronauts’ bone marrow at multiple time points before and after a six-month mission at the International Space

Station (ISS).

The researchers found a 4.2 per cent decrease in bone marrow fat about a month after returning to Earth.

This gradually returned to normal levels and was closely associated with increased production of red blood cells and restoration of bone.

“Since red blood cells are made in the bone marrow and bone cells surround 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 Dr Trudel. “We look forward to investigating this further in various clinical conditions on Earth.”

The research also suggests that younger astronauts may have an increased ability to harness the energy from bone marrow fat, and that female astronauts’ bone marrow fat increased more than expected after a year.

“I’m hopeful that this research will help people recover from immobility on Earth as well as in space,” said Dr Trudel.