Abstract
Purpose :
Keratoconus (KC) is a progressive, vision-threatening disease that is characterized by the thinning and bulging of the cornea. KC is found in both sexes and presents in second decade of life. Extracellular vesicles (EVs) are membranous structures that are shed from the plasma membrane or originate from the endosomal system. EVs transfer information, such as RNA and proteins, from one cell to another. We sought to describe and investigate morphology and biochemical signatures of EVs in tear film isolates from KC patients.
Methods :
Tears were collected from 10 healthy (5 males and 5 females) and 9 KC (4 males and 5 females) subjects. Tear samples were collected passively from the lateral meniscus of the eye using a glass capillary tube. Samples were processed and analyzed using the ExoViewTM R100.
Results :
Analysis demonstrated that KC tears had higher CD9+ and CD63+ than Healthy tears. KC had lower CD81+ than tears from healthy subjects. KC had higher CD81/CD9 colocalization than healthy. KCs had lower CD63/CD9 colocalization than healthy. KCs have lower CD63/81 when compared to healthy. Healthy and KC samples had the same expression of triple colocalization, CD63/CD81/CD9. Sex stratification revealed both KC males/females having higher CD9+ and CD63+ than healthy males/females. KC females had lower CD81+ than healthy females and KC males had a higher CD81+ populations when compared to healthy males. Our data also showed that KC males/females had higher colocalizations of CD81/CD9 when compared to healthy males/females. KC females also showed lower colocalization of CD63/81 than healthy females. KC males had higher colocalization of CD63/CD81 compared to healthy males. KC males/females had lower CD63/CD9 than healthy males/females. KC females had higher CD63/CD81/CD9 than healthy females and KC males had lower CD63/CD81/CD9 than healthy males. Both Healthy and KC derived EVs had a diameter range of 50 to 200nm, with the majority being between 50 and 80 nm suggesting a majority of exosome population and a minor population of apoptotic vesicles.
Conclusions :
For the first time, we were able to isolate and characterize tear EVs from KC subjects. The differences described suggest that there is a distinct phenotype present in KC-derived tear EVs when compared to healthy samples. Knowledge of these EV findings may help researchers and clinicians for future diagnosis and management of KC patients.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.