Abstract
Purpose :
Dry Eye Disease (DED) is a chronic, multifactorial disorder with multiple contributors that include abnormalities in the lacrimal glands, neurosensory systems, and/or tear composition and stability. DED has multiple sub-types, including decreased tear production (termed aqueous tear deficiency or ATD) and tear instability despite normal production (termed evaporative dry eye or EDE). EVs are small sphere-like structures that are produced from cells and have been reported as potential biomarkers for numerous inflammatory diseases. This study investigates differences in EV composition and characteristics in individuals with ATD and EDE and examines the contribution of race and age.
Methods :
Tears were collected from 9 controls, 8 ATD, and 8 EDE subjects using Schirmer strips. Controls were defined by a 5 item Dry Eye Questionnaire (DEQ-5) score<6, Schrimer>5 mm and tear break up time (TBUT) >5 seconds in both eyes; ATD by DEQ-5≥6 and Schirmer≤5 mm; and EDE by DEQ-5≥6, Schirmer>5 mm, and TBUT≤5 seconds in either eye. Tear samples were analyzed for EV-marker expression (CD63, CD81, and CD9 tetraspanins, in isolation or combination [CD63/81/9 co-expression]), particle size, and total count using the ExoViewTM R100. EVs composition were compared across DED groups, and the contribution of race and age to EV composition were compared within groups. All data are expressed in means.
Results :
The mean age of the population was 62±12 years with 87% identifying as male and 35% as White. The frequency of EVs co-expressing CD63/CD81/CD9 was higher in the ATD vs. EDE and control groups (ATD=3%; EDE=2%; C=1%, p<0.05). The frequency of EVs expressing CD63 was higher in the EDE vs. control group. Particle size was larger in the ATD and EDE groups vs. controls (ATD=54.2 nm; EDE=56.8 nm; C=53.8 nm, p<0.001). EV total counts were similar across groups. Within groups, Blacks with ATD had a higher frequency of EVs expressing CD9 vs. Whites (B=25%; W=16%, p=0.03). In the EDE group, Black had a higher frequency of EVs co-expressing CD63/CD81/CD9 vs. Whites (B=2%; W=1%, p<0.05). Size and total particle count did not vary by race and EV parameters were not impacted by age.
Conclusions :
We determined that the ATD and EDE groups displayed unique EV phenotypes when compared to controls. Additionally, we found that race also impacted EV phenotypes. Future studies are needed to examine the potential of EV “signatures” as diagnostic tools in DED.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.