Abstract
Purpose :
Type 2 diabetes (T2D) is a strong risk factor for developing dry eye disease (DED), a common condition which negatively affects quality of life, QoL (Yazdani-Ibn-Taz et al., 2019). The link between T2D & DED is not understood, but research shows increased tear levels of the cytokine epidermal growth factor (EGF) in T2D+DED patients versus DED-only (Liu et al., 2019).
This study aimed to investigate a panel of tear inflammatory proteins, alongside ocular surface health and DED symptoms, in those with T2D+DED (versus DED-only), to determine if they have a role in its pathophysiology. We also investigated how DED affects the QoL of these groups.
Methods :
122 subjects were divided into 4 groups: T2DM+DED (n=47), T2D-only (n=41), DED-only (n=17) and controls (n=17). Tear samples were analysed for 14 cytokines (EGF; Fracktalkine; IFN-γ; IL-10; IL-1RA; IL-1β; IL-2; IL-4; IL-6; IL-8; IP-10; MCP-1; TNF-α & VEGF) via multiplex cytometric bead array (EMD Millipore Corporation, UK). Clinical ocular surface health measures (Schirmer, fTBUT & CFS) and DED-related symptoms/QoL were measured (OSDI/DEQS questionnaires).
Results :
Out of 14 cytokines analysed, 11 were detectable in >50% samples (IL-1RA, IL-6, IL-8, EGF, Fracktalkine, IL-1β, IL-10, IP-10, MCP-1, TNF-α & VEGF). Three cytokines, IL-6, IL-8 & IL-1RA, were significantly different across the 4 groups.
IL-6 levels were significantly raised in T2D+DED versus DED-only, T2D-only and controls (all p<0.05).
IL-8 levels were significantly higher in T2D+DED versus DED-only, T2D-only and controls (p<0.05).
IL-1RA was significant lower in T2D-only versus T2D+DED & controls (both p<0.05).
In T2D+DED, IL-6 & IL-8 levels were positively correlated with ocular staining (CFS), while IL-6 was inversely correlated with fTBUT. There was a significant positive relationship between DED severity and QoL in T2D+DED group and DED-only (both p<0.001).
Conclusions :
The current study showed, for the first time, that tear fluid IL-6 and IL-8 concentrations could potentially be diagnostic biomarkers of T2D-related DED. The CFS scores were highest in the T2D+DED group, which might be attributable to the increased levels of IL-6 and IL-8. Moreover, it was noted that the T2D+DED group had more patients with moderate and severe DED (versus DED-only), suggesting a different pathogenesis of DED severity in T2D versus in those with DED-alone.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.