Purpose: The purpose was to compare aqueous inflammatory and angiogenic cytokine levels in diabetic macular edema (DME).
Materials and methods: Aqueous samples were obtained from 50 eyes with DME and 12 normal eyes (control group). DME was classified according to the morphologic pattern based on optical coherence tomography: Diffuse retinal thickening (DRT; n = 19), cystoid macular edema (CME; n = 17), or serous retinal detachment (SRD; n = 14). Aqueous samples were collected just before intravitreal injection and at the beginning of cataract surgery in the control group. Interleukin (IL)-6, IL-8, interferon-induced protein (IP)-10, monocyte chemotactic protein (MCP)-1, platelet-derived growth factor (PDGF)-AA, and vascular endothelial growth factor (VEGF) levels were measured by multiplex bead assay.
Results: The IL-6, IL-8, IP-10, and PDGF-AA levels differed significantly among the three groups of DME (P = 0.014, P = 0.038, P = 0.021, and P = 0.041, respectively). However, there were no differences between groups in aqueous concentration levels of MCP-1 and VEGF (P = 0.205 and P = 0.062, respectively). IL-6 (P = 0.026) and IL-8 (P = 0.023) correlated positively with central foveal thickness (CFT) in the CME group. None of the cytokine levels correlated significantly with CFT in any of the DRT and SRD groups.
Conclusions: Aqueous concentrations of cytokines varied according to the morphologic pattern of DME, which might explain the variable response to treatments such as intravitreal bevacizumab or triamcinolone injection.