Vitreous Levels of Interleukine-8 (il-8) and Monocyte Chemoattractant Protein-1 (mcp-1) in Patients With Macular Edema Secondary to Retinal Vein Occlusions

Abstract

Purpose: : To investigate a possible relationship between interleukine-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) and macular edema secondary to retinal vein occlusions (RVO), we determined vitreous levels of theses peptides in patients with this condition and compared them with levels in control subjects. We also investigated the correlation between macular thickness, final visual acuity and vitreous levels of IL-8 and MCP-1 in patients with RVO.

Methods: : Undiluted vitreous and serum samples were obtained at the time of vitrectomy from patients with macular edema secondary to RVO and controls (macular hole,epiretinal membrane). IL-8 and MCP-1 were measured by ELISA.

Results: : Vitreous and serum samples were obtained from 20 eyes (19 patients) with RVO, 14 branch retinal vein occlusions and 6 central retinal vein occlusions and from 9 controls. Vitreous levels of both chemokines were significantly higher in patients with RVO compared with control subjects: IL-8: 63.7 pg/mL (25-240.2) vs 5.1 pg/mL(2.3-18.3), p<0.001; MCP-1: 1520.4 pg/mL (462.2-3445.3) vs 746 pg/mL (479.7-980.3), p<0.001. We did not observe differences in serum levels of both chemokines between patients with RVO and control subjects. Vitreous levels of IL-8 and MCP-1 were significantly higher than serum levels in patients with RVO: IL-8: 63.7 pg/mL (25-240.2) vs 7.5 pg/mL (1.3-23.8), p<0.001; MCP-1: 1520.4 pg/mL (462.2-3445.3) vs 312 (134.5-694), P<0.001.A negative correlation was observed between vitreous IL-8 levels and reduction of macular thickness at 3 months follow-up (p=0.048).We conducted this study in accordance with the Declaration of Helsinki

Conclusions: : We have found elevated vitreous levels of IL-8 and MCP-1 in patients with RVO. We have not found significant differences in serum concentracions of both chemokines among groups and vitreous levels of both IL-8 and MCP-1 were higher than serum levels in patients with RVO. These results suggest that production of both chemokines is locally upregulated in eyes with RVO and that they may be related with the pathogenesis of complications such as macular edema. We have found a negative correlation between IL-8 levels and reduction of macular edema at three months follow-up, which suggests that this chemokine may have a more relevant role than MCP-1 in the pathogenesis of macular edema.

Keywords: vascular occlusion/vascular occlusive disease • edema • macula/fovea