Researchers from Arizona State University (ASU) and NASA believe that an inorganic analysis technique developed in the Earth sciences may be useful in a clinical setting for the more rapid and sensitive detection of bone deterioration.
Millions of people – especially among elderly members of the population – are affected each year by osteoporosis, a disease which weakens the bones.
"Bone loss also occurs in a number of cancers in their advanced stages," commented Professor Ariel Anbar, a senior author of the study. "By the time these changes can be detected by X-rays, as a loss of bone density, significant damage has already occurred. Also, X-rays aren’t risk-free. We think there might be a better way."
The findings of the research appeared in the online edition of Proceedings of the National Academy of Sciences
) this week. Atoms of an element with different atomic mass are known as isotopes, and isotopes of calcium are absorbed by bone at different rates according to how heavy or light they are. This means that the ratio of calcium isotopes which occur naturally in urine reflect the health – or otherwise – of an individual’s bones.
Although the effect of disease on calcium isotope ratios is complex, a mathematical model developed 15 years ago by Joseph Skulan and updated by Stephen Romaniello predicts the impact it will have. The effect is also on a very small scale, but can be detected with sensitive mass spectrometry as developed by lead author Jennifer Morgan and her colleagues at ASU.
The NASA-funded trial study looked at 12 healthy participants who were confined to bed for 30 days. When the weight on bones such as those in the spine and legs is relieved, for example when you lie down, it is known as ‘skeletal unloading’. Over long periods of time, this results in bone deterioration.
"NASA conducts these studies because astronauts in microgravity experience skeletal unloading and suffer bone loss," explained co-author Scott M. Smith, a NASA nutritionist. "It’s one of the major problems in human spaceflight, and we need to find better ways to monitor and counteract it. But the methods used to detect the effects of skeletal unloading in astronauts are also relevant to general medicine."
Inorganic signatures could result in diagnostic tools and monitoring techniques for all sorts of health problems as many diseases cause subtle changes in the balance and composition of isotopes of various elements in the body.
"This is a ‘proof-of-concept’ paper," Professor Anbar added. "We showed that the concept works as expected in healthy people in a well-defined experiment. The next step is to see if it works as expected in patients with bone-altering diseases. That would open the door to clinical applications."