Purpose
To evaluate the relationship between various cytokine levels in aqueous humor and diabetic macular edema (DME) patterns determined by optical coherence tomographic (OCT).
Methods
This prospective, interventional, comparative study examined 76 patients with DME. Ten patients who underwent cataract surgery served as controls. Eyes with DME were divided into four groups, based on OCT patterns of DME, prior to intravitreal bevacizumab injection (IVB). Patterns included sponge-like diffuse retinal thickening (SDRT), cystoid macular edema (CME), serous retinal detachment (SRD), and combined CME and SRD. Visual acuity, central macular thickness (CMT), and aqueous cytokine concentrations of interleukin (IL)-6, IL-8, IL-10, IL-13, monocyte chemo attractant protein-1 (MCP-1), vascular endothelial growth factor (VEGF) were measured. The odds ratio (OR) between aqueous cytokines level and each DME pattern were calculated using multivariate regression analysis.
Results
After IVB, CMT was reduced in all groups, but the highest reduction ratio occurred in eyes with SDRT and CME. Aqueous analyses showed that VEGF was associated with SDRT and Combined pattern (P = 0.003, OR = 1.043, 95% confidence interval [CI] = 1.015-1.072, P = 0.038, OR = 1.014, 95% CI = 1.014-1.043, respectively). IL-6 and MCP-1 were associated with CME (P < 0.001, OR = 1.025, 95% CI = 1.011-1.039, and P < 0.001, OR = 1.003, 95% CI = 1.001-1.004, respectively). IL-6 was also associated with SRD and Combined pattern (P = 0.045, OR = 1.018, 95% CI = 1.006-1.030, P = 0.031, OR = 1.013, 95% CI = 1.002-1.024, respectively).
Conclusions
IL-6 is highly associated with CME, SRD, and combined pattern and VEGF is significantly associated with SDRT, CME, and combined pattern. Different cytokines may play an important role in the development of DME subtypes determined by OCT patterns.