Microscopic "bubbles" in tears can help to diagnose eye diseases, and potentially even neurodegenerative diseases and cancer. Doctors could soon have the power to diagnose illnesses with just a teardrop. In a new study, scientists have shown it’s possible to identify biomarkers for diseases in human tears, offering a new and non-invasive way to pinpoint diseases. The new research was reported today in the journal ACS Nano. Researchers from Wenzhou Medical University in China developed a system that harvests and purifies tiny blobs called exosomes from tears, which they call Incorporated Tear Exosomes Analysis via Rapid-isolation System,” or iTEARS for short. Exosomes are extracellular vesicles released by cells, typically 30 to 150 nanometers in diameter – much smaller than most bacteria. Think of them as minuscule bubbles that can transport useful things – such as nucleic acids, proteins, lipids, and metabolites – to neighboring cells like a tiny postman. If you take a deeper look at the contents of an exosome, you can gain all kinds of insights into the health of a person. The presence of a particular protein in an exosome, for instance, could be a clue that the person has a particular disease. Scientists have previously found a way to isolate and analyze exosomes from pee and blood plasma, but this latest study was keen to see whether the same could be done with tears. Using their iTEARS system, the team was able to successfully distinguish between healthy people and patients with various types of dry eye disease based on over 400 different types of proteins found in tears’ exosomes. Amazingly, it was able to do this in just 5 minutes. They were also able to do the same with people with diabetic retinopathy, a complication of diabetes that involves damage to the back of the eye, by looking for the presence of certain bits of genetic material (MicroRNAs) in the exosome. The researchers are optimistic that this is just the beginning of iTEARS. They’re confident that the system has the potential to use tears to diagnose conditions that don’t even directly affect the eye, including neurodegenerative diseases and cancer. As shown by previous studies, we already know that certain biomarkers in tears are a solid indication that a patient may be experiencing breast cancer. By looking at the contents of the tiny exosomes, it may be possible to gain an even more sensitive and precise view of these types of biomarkers that indicate disease. With a few tweaks and a bit of fine-tuning, the researchers on the iTEARS project say a person could theoretically take a trip to the doctor, shed a tear, and know whether they are in the early stages of disease within minutes. “In conclusion, we establish the iTEARS for deciphering the secrets of diseases from a teardrop, which reveals the promising role of tear exosomes in disease classification and course monitoring of ocular disorders and other diseases such as neurodegenerative diseases and cancer,” the study authors write. “By being applied in extended disease types and validated with abundant clinical cases, we anticipate our teardrop-based iTEARS to be the alternative tool for point-of-care-test.” Source
