Identification of a Suitable Marker for prognosticating the therapy of DR with DME

Abstract

Purpose : Patients of diabetic retinopathy (DR) with diabetic macular edema (DME) currently receive intravitreal injections of anti-VEGF and steroid yielding a variable and unpredictable response. Herein, we assessed the potential of inflammatory markers in different ocular fluids for monitoring their responses in post-clinical management of DR with DME.

Methods : The study was conducted on vitreous humour (VitH) of PDR with DME, DM without DR and control subjects to identify the potential markers. VitH proteomics was accomplished by LC-MS-MS analysis on three samples from each category. The acquired raw data was analyzed using standard bioinformatics and proteomics tools (MaxQuant) and searched against the known human vitreous proteome data. Selected proteins based on their functional relevance and statistical significance from differentially regulated pathways were validated in VitH samples of PDR (n=30) and controls (n=30) using ELISA and further assessed in tear samples of patients of DM (n=15) and DR with DME (n=23) collected at baseline and 4- and 8-weeks following injections of anti-VEGF and steroids to understand their potential as prognostic markers. Statistical significance was calculated using the student’s t-test.

Results : A total of 1079 proteins including 16 novel ocular proteins were identified with at least one unique peptide along with an FDR (false discovery rate) of 0.05%. The top identified proteins belonged to angiogenesis, inflammation, extracellular matrix, apoptosis, and autophagy pathways and were confirmed by ELISA. The MMP9, IL-8, VEGFR1, VEGF, Lipocalin-2, PDGF-AA, ICAM-1 and THBS2 proteins were significantly upregulated (p<0.05) in the PDR vitreous. In addition to these, the TNF-α, IL-10, IFN-γ, IL-17a proteins were also upregulated in the tear samples (n=23). The expression of all these markers decreased following steroid therapy (n = 16), but only a few after anti-VEGF injection (n = 5). Among them, IL-17a significantly correlated with OCT-based CMT (central macular thickness) [OR = 15 (CI- 1.21 -185.21); p-value =0.03] and showed a trend [OR = 23.00 (CI- 0.94-561.80); p-value = 0.054] for inner retinal fluid accumulation in the treated DME patients

Conclusions : Tear cytokine levels may serve as potential, non-invasive, prognostic markers for DR with DME that warrants further investigations.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.