Inflammatory mediators in the vitreal reflux of patients with diabetic macular edema

Abstract

Purpose: To quantify inflammatory, growth/angiogenic, and tissue remodeling mediators in vitreal reflux (VR) in patients with diabetic macular edema (DME), as collected at first and third intravitreal anti-vascular endothelial growth factor (anti-VEGF, ranibizumab) injection.

Methods: Thirty (30) consecutive patients (type-2 diabetes mellitus) with visual impairments due to DME and undergoing the first (untreated DME) or the third (treated DME) intravitreal injection of anti-VEGF were included in the study. At the time of surgery, patients were subjected to clinical assessment and spectral domain-optical coherence tomography (SD-OCT), including central retinal thickness (CRT), macular volume, and outer nuclear layer/retinal pigment epithelial (ONL/RPE) measurements. VR sampling was performed at the time of needle removal and subjected to customized protein-array, Western blotting (WB), Ella™ microfluidic, and/or enzyme-linked immunosorbent assay (ELISA) analysis. Biostrumental and biochemical data were collected just prior to the surgery and are representative of disease state. Clinical, biostrumental, and numerous biomarkers and cytokines were statistically compared.

Results: Decreased CRT values were detected in treated DME retinas, as compared to untreated ones (p ≤ 0.05). Differences in VEGF and other mediator expressions between treated and untreated DME were detected in VR samples. Particularly, osteopontin (p ≤ 0.05), interleukin 6 (IL6) (p ≤ 0.05), and VEGF (p ≤ 0.1) values were decreased after treatment. Significant changes were validated by WB, ELISA, and Ella™ analysis.

Conclusion: Overall, the biostrumental and biochemical data suggest the presence of a specific pattern of inflammation in VR after treatment. The data would suggest the presence of other mechanisms and mediators, in addition to VEGF, accountable for DME progression.

Keywords: Anti-VEGF; DME; Inflammation; Osteopontin; Vitreal reflux.