Role of Cytokines in Ranibizumab Therapy for Macular Edema in Patients with Central Retinal Vein Occlusion

Purpose: To investigate aqueous humor levels of 11 factors/cytokines in patients with central retinal vein occlusion (CRVO) and macular edema (ME) receiving anti-vascular endothelial growth factor (VEGF) therapy, as well as correlations between changes of functional or morphological parameters and aqueous cytokine levels. Methods: In 32 CRVO patients scheduled to receive 2 consecutive doses of intravitreal ranibizumab, aqueous samples were obtained at the time of injecting each dose. Aqueous levels of VEGF, soluble VEGF receptor (sVEGFR)-1, sVEGFR-2, platelet-derived growth factor-AA (PDGF-AA), placental growth factor (PlGF), interleukin-6, and monocyte chemotactic protein-1 (MCP-1) were measured using a suspension array. Results: Aqueous humor levels of VEGF, sVEGFR-1, PDGF, PlGF, interleukin-6, and MCP-1 were all significantly lower at 1 month after the initial dose of intravitreal ranibizumab compared with baseline. A significant negative correlation was noted between the change of ME and the changes of aqueous humor VEGF or interleukin-6 levels after intravitreal ranibizumab. The change of VEGF also showed a significant negative correlation with improvement of visual acuity. Conclusions: In patients with CRVO, the changes of visual acuity and ME after intravitreal ranibizumab were associated with inhibition of intraocular VEGF production. VEGF could be a useful marker for the response of ME to treatment.