Tears for diagnosis
Scientists have proposed to diagnose diseases by analyzing tears
Daniil Sukhinov, Naked Science
In order to make a correct diagnosis of the patient, it is necessary to reliably assess the symptoms that he has, which can often be invisible in the early stages or change with the progression of the disease. To improve the accuracy, speed and convenience of making diagnoses, modern clinical research is aimed at developing non-invasive methods for simultaneous detection of a number of diseases.
Analysis of exosomes — nanoscale extracellular vesicles containing various metabolites, proteins, lipids and regulatory RNAs — is just one of such promising non-invasive diagnostic methods. It allows you to obtain reliable information about the state of exosome-producing cells and tissues, identify biological markers of diseases in the contents of these bubbles, which will help to make the correct diagnosis with high accuracy, as well as monitor the development or success of treatment of progressive diseases. Exosomes can be found in a variety of biological secrets of the body — blood, urine, saliva and tears.
However, modern methods of isolating exosomes from samples of biological fluids require lengthy and complex processing stages or large volumes of material. Tears are well suited as a material, since they can be collected quickly and non-invasively, although in extremely small quantities.
Therefore, researchers from Wenzhou Medical University (China) and Harvard Medical School (USA) have developed a special nanoporous membrane system for analyzing exosomes from lacrimal secretions, capable of working with such micro-volumes. The scientists described their system in detail in an article published in the journal ACS Nano of the American Chemical Society (Hu et al., Discovering the Secret of Diseases by Incorporated Tear Exosomes Analysis via Rapid-Isolation System: iTEARS).
The development of the research team is essentially a modification of the original system that worked with urine and blood plasma samples. After collecting samples, a system called iTEARS ("integrated analysis of lacrimal exosomes using a rapid isolation system"), in just five minutes of filtration through nanoporous membranes, allows you to isolate exosomes from lacrimal fluid. Then nucleic acids and proteins are isolated from these extracellular vesicles and analyzed on another device.
The analysis of more than 900 proteins obtained from exosomes made it possible to successfully distinguish patients with different types of dry eye syndrome and distinguish those who did not have any ophthalmological diseases. Similarly, iTEARS helped to record differences in the composition of exosomal microRNA in patients with diabetic retinopathy and healthy people. Moreover, the authors suggest that their system can also track the progression of this disease over time.
Scientists are confident that their work will lead to the creation of a more sensitive, rapid and minimally invasive molecular diagnosis of not only various eye diseases, but also many systemic (affecting several organs and tissues at once), neurodegenerative and cancerous diseases using just a few tears.
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