Aqueous Humor Proteome Associated with Incomplete Anti-VEGF Response in Diabetic Macular Edema

Abstract

Purpose : Incomplete response to anti-VEGF therapy is a substantial clinical challenge in the management of eyes with diabetic macular edema (DME), and underlying intraocular proteome changes remain incompletely defined.

Methods : Aqueous humor from treatment naïve patients with clinically significant DME (n = 28) and age-matched controls (n = 19) was collected. Aqueous samples were also collected from DME patients undergoing anti-VEGF therapy having reached their plateau phase and classified as either incomplete anti-VEGF response (n = 11), minimal fluid (n = 8), or no fluid (n = 11). Incomplete response was defined as persistent, clinically meaningful central DME despite adequate anti-VEGF dosing. Best corrected visual acuity (BCVA) was recorded in LogMAR and the severity of DME was assessed as central subfield thickness (CST) by OCT. Proteome analysis by label-free liquid chromatography – tandem mass spectrometry was performed. Proteins were considered significantly regulated if p < 0.05 at a false discovery rate at 0.05. A human donor eye with treatment naïve DME and a control eye were used for immunofluorescence.

Results : A total of 891 proteins were identified in the combined set of aqueous samples. Treatment naïve DME was associated with VEGF signaling, inflammatory response, vascular occlusion, hypoxia inducible factor-1 (HIF-1) signaling, complement activation, extracellular matrix-receptor interaction, and glucagon signaling. Proteomic analysis and ELISA demonstrated high levels of VEGF and proteins involved in monocyte recruitment in untreated DME. In treatment naïve DME, proteins involved in complement signaling correlated with BRVA and CST while proteins involved in maintenance of barrier functions, were downregulated in DME and correlated negatively with CST. Immunofluorescence confirmed an upregulation of proteins involved in vascular occlusion at the retinal level. Samples from patients undergoing anti-VEGF therapy (incomplete response, minimal fluid or no fluid) are being processed.

Conclusions : The proteome analysis identified multiple proteins from distinct signaling pathways that correlated with disease state and severity. Elevated levels of pro-inflammatory proteins were observed in DME while proteins involved in maintaining barrier integrity were reduced. This data provides insights into DME pathophysiology and potential targets for novel therapeutic approaches.

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