Aqueous Humour Cytokine Levels May Predict Diabetic Macular Edema Response to Intravitreal Dexamethasone Implant Injection

Abstract

Purpose : To determine whether baseline cytokine aqueous humour (AH) levels are associated with diabetic macular edema (DME) response to dexamethasone intravitreal implant (DEX) injection.

Methods : Case series study of 59 adults with diabetes mellitus, centre-involving DME (59 eyes) and central subfield macular thickness (CSMT) >300 μm on spectral domain optical coherence tomography (OCT) receiving DEX treatment. Exclusion criteria was defined on proliferative retinopathy, intravitreal injection of any kind within 6 months and prior ocular surgery beyond uncomplicated cataract removal. Best-corrected visual acuity (Snellen chart), intraocular pressure and OCT exploration (standard Macular Cube 518x128 μm scan on Cirrus, Carl-Zeiss Meditec Inc., Dublin, CA, USA) were carried out prior to treatment and 4-8 weeks afterwards. Anterior chamber tap with AH sampling was performed at DEX injection time. Multiplex immunossay was undertaken for interleukin (IL)-1β, IL-6, IL-8, IL-10, interferon gamma-induced protein (IP)-10, monocyte chemoattractant protein (MCP)-1, tumor necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF). Main outcome measure was set on correlation between baseline AH mediators levels and CSMT and macular volume (MV) change after DEX injection.

Results : Higher IL-6, IL-8, IP-10 and MCP-1 levels correlated to greater decreases in absolut MV (mean -1.46 ± 1.26 mm³): IL-6 (r=-0.352, p=0.006), IL-8 (r=-0.365, p=0.004), IP-10 (r=-0.298, p=0.022) and MCP-1 (r=-0.333, p=0.010). Accordingly, relative MV change (mean -10.96 ± 8.25 %) was also related to IL-6 (r=-0.333, p=0.010), IL-8 (r=-0.361, p=0.005), IP-10 (r=-0.314, p=0.015) and MCP-1 (r=-0.310, p=0.017). In addition, relative CSMT change (mean -27.22 ± 16.83 %) was associated to baseline levels of IP-10 (r=-0.290, p=0.026).

Conclusions : Baseline AH levels of IL-6, IL-8, IP-10 and MCP-1 could be considered predictors of OCT-based DME response to DEX treatment. As a whole, our findings enforce clinical knowledge on DEX action on DME cases and could support future studies on treatment individualization of such a disease.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Statistically signficant correlations between IL-6, IL-8, IP-10 and MCP-1 aqueous humour levels (pg/ml) and OCT-based macular volum (mm³) absolut change (ChMV) due to intravitreal dexamethasone implant injection for DME. Showing drawn line as correlation. Note Y-axis set on logaritmic scale.