Many of us dread the inevitable needle prick at the doctor’s office to draw blood, not to mention even more invasive diagnostic tests (colonoscopy, anyone?). Wouldn’t it be easier if we could just spit or pee in a cup, and from the spectrum of miRNAs in the fluid, our doctor could tell us whether or not we have a clean bill of health?
For sure, miRNA biomarkers offer some advantages over proteins, such as reduced complexity in body fluids, a lack of posttranslational modifications, and simple detection with complimentary oligonucleotides. But before miRNAs can enter the diagnostic toolkit, researchers need to determine their distributions in fluids from healthy and sick patients.
So a team of researchers led by Kai Wang at the Institute for Systems Biology in Seattle examined miRNAs in 12 body fluids from normal individuals: plasma, saliva, tears, urine, amniotic fluid, colostrum, breast milk, bronchial lavage, cerebrospinal fluid, peritoneal fluid, pleural fluid, and seminal fluid. They also looked at miRNA distribution in urine from people with urothelial conditions such as pregnancy, renal cancer, and bladder cancer.
- miRNAs were found in all fluids tested, with distinct compositions in different fluid types.
- Some miRNAs were common to multiple fluids, whereas others were enriched in specific fluids
- miRNAs showed distinct patterns in urine from individuals with various urothelial conditions
These findings support the idea of using miRNAs as disease biomarkers. Take a non-invasive look for yourself at Clinical Chemistry, September 2010.