Systemic Inflammatory Mediator Levels in Non-Proliferative Diabetic Retinopathy Patients with Diabetic Macular Edema

To study the systemic inflammatory mediator levels in non-proliferative diabetic retinopathy (NPDR) patients with diabetic macular edema (DME) and explore the correlation between systemic inflammatory mediators and DME.

In this prospective study, we included 25 patients without diabetes (control group) and 75 patients with type 2 diabetes mellitus (diabetic group). According to fundus examination, the diabetic group patients were divided into: diabetic patients without diabetic retinopathy (DR) (Non-DR group), NPDR patients without DME (Non-DME group), and NPDR patients with DME (DME group). Serum levels of a broad panel of inflammatory mediators were analysed by multiplex protein quantitative detection technology based on a flow cytometry detection system.

The interferon-γ (IFN-γ) levels were significantly higher in DME group and Non-DME group as compared to control group (p = 0.023 and p = 0.033) and Non-DR group (p = 0.009 and p = 0.015). Significantly higher values were obtained in DME group and Non-DME group as compared to control group for the interleukin-8 (IL-8) (p = 0.003 and p = 0.003). The IL-23 levels were significantly elevated in DME group and Non-DR group than in Non-DME group (p = 0.013 and p = 0.004). The diabetic group had significantly higher serum levels of IL-8 and IL-33 (p = 0.001 and p = 0.011), and lower serum levels of tumor necrosis factor-α (TNF-α) (p = 0.027) in comparison with control group.

The changed levels of serum inflammatory mediators suggest that the systemic inflammatory mediators are involved in the pathogenesis of NPDR patients with DME. Such effects can guide clinical monitoring, diagnostic and therapeutic approaches for DME patients at an early stage.