Real-Time Monitoring of Bone Diseases!

Now that a group of geochemists, biologists and clinicians have come together, patients may now be able to benefit from near real time monitoring of bone diseases. The researchers, from Arizona State University and Mayo Clinic, have worked with NASA to develop a new, rapid test of bone health. The test, which measures changes in calcium isotope ratios, has been validated on blood samples from NASA space shuttle astronauts.

As indicated in the August 17, 2015 news release, “These methods, using mass spectrometry, can discern the relative ratios of the calcium isotopes 42Ca and 44Ca in bone. The researchers found that lighter calcium isotopes, such as 42Ca, are absorbed from the blood into the bone during bone formation. Conversely, these light isotopes tend to be released into the bloodstream when bones break down. By measuring the ratios of the two isotopes in blood or urine scientists can calculate the rate of change of bone mass.”

“The research was piloted in bed-bound subjects, but the best way for the researchers to test whether the system worked was in an ambient and less controlled population who are known to experience rapid bone loss. In space, because of zero gravity conditions, astronauts experience very rapid bone loss. Working with NASA, the researchers 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.”

According to lead researcher, Ariel Anbar, Ph.D., a biogeochemist with Arizona State University, “We were able to confirm that Ca isotopes of the shuttle shifted as expected, meaning that they 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.”

“The big advantage of these measurements is that they show what is happening in the bone, whereas traditional bone health measurements, such as DXA scans, show what has happened. 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.”

Dr. Anbar told OTW, “The most important thing I can think of for orthopedic surgeons to know is that it has the potential to provide a (relative to X-ray) rapid assessment of whether a patient is gaining or losing bone mass. I can imagine that would be useful to surgeons in some instances. The method also could provide insight into the basic dynamics of bone biology that might be of use to evolution of surgical practice, but I’m way outside my depth there.”

“The basic concept works now. What we need to meet the goal of being ‘widely available’ is focused R&D in two directions: a) Clinical research to determine how well it works in real populations with real disease; b) Engineering-type research to transform what is now a labor-intensive (hence, expensive) analysis into something more efficient and routine, requiring less expertise from the analyst. This is quite doable, but requires time.”

“I would say that we are probably five years away (i.e., one good clinical study) from this being available in a way that is useful to guide patient care for certain diseases where cost is less of an object than in ‘wide monitoring, ’ and probably a decade away from a true “wide monitoring” tool—that requires that we really beat down the cost and complexity.”