One advantage of the approach is that it surveys the workings of the entire body with a single measure. In addition to simplifying diagnosis, it could also provide rapid feedback about the effectiveness of treatments.
"The pattern of these ratios in blood or breath is different for different diseases for example cancer, diabetes, or obesity which makes this applicable to a wide range of diseases," explains Assadi-Porter.
The technology relies on the fact that the body uses different sources to produce energy under different conditions. "Your body changes its fuel source. When we're healthy we use the food that we eat," Porter says. "When we get sick, the immune system takes over the body and starts tearing apart proteins to make antibodies and use them as an energy source."
That shift from sugars to proteins engages different biochemical pathways in the body, resulting in distinct changes in the carbon isotopes that show up in exhaled carbon dioxide. If detected quickly, these changes may signal the earliest stages of disease.
The researchers found similar patterns using two independent assays nuclear magnetic resonance spectroscopy on blood serum and cavity ring-down spectroscopy on exhaled breath. The breath-based method is particularly exciting, they say, because it is non-invasive and even more sensitive than the blood-based assays.
In the mice, the techniques were sensitive enough to detect statistically significant differences between even very small populations of healthy and sick mice.
The current cavity ring-down spectroscopy analysis
|Contact: Fariba Assadi-Porter|
University of Wisconsin-Madison