Tears could help doctors diagnose eye diseases

By Danny Halpin via SWNS

Doctors may soon be able to diagnose eye diseases by analyzing tears, according to a new study.

Researchers have developed a nanomembrane system which harvests and purifies tiny blobs called exosomes from tears and allows them to check for signs of disease.

Dubbed iTEARS, the system could lead to more efficient and less invasive diagnoses for disease and conditions without relying on symptoms alone.

Currently, diseases are identified by assessing a patient’s symptoms, which can slip by undetected in the early stages or be unreliably reported.

Other methods of testing samples of proteins or genes could improve the accuracy of diagnoses but they are long and complicated and need large sample volumes.

Tears are much better suited for samples because the fluid can be collected quickly and non-invasively, although only tiny samples can be harvested at a time.

Study co-author Dr. Luke Lee said: “Exosomes with membrane structures can encapsulate and protect their cargos, thus becoming a promising source for disease early detection.

“Tears can be non-invasively and self-collected from patients for exosome analysis.

“However, the tear-exosome-based disease analysis has rarely been reported so far.

“Recording exosomes from trace samples for further analysis is necessary in exploring the tear-exosome-based disease world.”

Dr. Lee, Dr. Fei Liu and colleagues wondered if a nanomembrane system which they had originally developed for isolating exosomes from urine and plasma would work for tears.

Publishing their findings in ACS Nano, the team modified their original system to handle the low volume of tears.

The new system, called Incorporated Tear Exosomes Analysis via Rapid-isolation System (iTEARS), separated out exosomes in just five minutes by filtering a tear solution over membranes and changing the pressure to stop them clogging.

Researchers tagged proteins from the exosomes with fluorescent markers while they were still on the device and then transferred them to other instruments for further analysis. They also extracted and analyzed nucleic acids.

Through this they were able to distinguish between healthy people and patients with various types of dry eye disease.

iTEARS also allowed the researchers to see differences in microRNAs between patients with a condition called diabetic retinopathy and those without any condition, suggesting that the system could help track how disease develop.

The team says the work could lead to a more sensitive, faster and less invasive diagnosis of various disease – using only tears.