Samples From ISS Astronauts Help Develop Real-Time Bone Test

After analysing blood samples from Nasa astronauts, a team of US geochemists is set to develop a new bone test that will offer the possibility of near real-time monitoring of bone diseases such as osteoporosis and multiple myeloma (a form of bone cancer).

The researchers from Arizona State University and Minnesota-based Mayo Clinic measured calcium isotope ratios in urine from 30 shuttle astronauts - before, during and after the flights.

This allowed them to confirm that the test worked at high sensitivity.

"The big advantage of these measurements is that they show what is happening in the bone, whereas traditional bone health measurements show what has already happened," explained lead researcher Ariel Anbar from Arizona State University in a statement.

Using mass spectrometry, the new method can discern the relative ratios of the calcium isotopes 42Ca and 44Ca in bone.

By measuring the ratios of the two isotopes in blood or urine, scientists can calculate the rate of change of bone mass.

"This means that we can have a real near-time view of what is happening in the bone, rather than comparing before and after, when damage may have already been done," he noted.

In space, because of zero gravity conditions, astronauts experience very rapid bone loss.

"We were able to confirm that Ca isotopes of the shuttle shifted as expected, meaning that we could see in more or less real time the ongoing bone loss. We did this using a simple urine sample, taken at various points during their flights," Anbar elaborated.

The researchers also looked at a group of 71 patients who either had multiple myeloma (bone cancer) or were at risk of multiple myeloma.

"Those patients who tended to lose the lighter 42Ca isotope seemed to be the ones where the cancer was the most active," the authors noted.

This means that the tests could feed into decisions on whether or not to treat a patient, for example if a cancer was dormant or growing very slowly, and to assess the effectiveness of treatments.

"From a scientific point of view, we are delighted that we have the chance to combine geochemistry, biology, and space science to benefit patients," Anbar said.

"By using calcium isotope ratios, healthcare providers may be able to optimise therapies for these debilitating illnesses in the future," commented Scott Parazynski, former Nasa astronaut.