Erythropoietin Is Not Related to Macular Edema Secondary to Retinal Vein Occlusions

Abstract

Purpose:: Erythropoietin (EPO) is a glycoprotein with a well known erythropoietic function and possibly with neurotrophic activity for retina. Last year, a role in proliferative diabetic retinopathy was suggested and we've recently found high levels of this factor in patients with diabetic macular edema without ischaemia. The aim of this study was to assess if EPO is also related to macular edema secondary to retinal vein occlusions (RVO). To elucidate this issue we studied vitreous levels of this factor in patients with the mentioned condition. We also assessed a possible correlation between EPO levels and macular thickness measured with OCT.

Methods:: Vitreous and serum samples were obtained from 12 patients with macular edema secondary to RVO (9 patients with central retinal vein occlusion and 3 with branch retinal vein occlusion) and 20 controls (10 patients with idiopatic epiretinal membrane and 10 patients with macular hole) who underwent vitrectomy. Erythropoietin was measured by RIA. Statistics: Man-Whitney test (comparation of EPO levels) and Pearson's test (correlation with macular thickness).

Results:: No differences were found between both groups neither in intravitreal erythropoietin levels nor serum erythropoietin levels. (Intravitreal concentrations: RVO: 69 mU/mL [27-800] vs controls: 25 mU/mL [10-75],p=ns; serum concentrations: RVO: 8.9 mU/mL [7-20.8] vs controls: 8.6 mU/mL [4.1-19], p=ns).No correlation was observed between EPO levels and macular thickness (r-0.209, p=0.514).

Conclusions:: Intravitreal erytropoietin levels are normal in patients with macular edema secondary to retinal vein occlusions which suggests that this factor is not involved in the pathophysiology of this condition.

Keywords: growth factors/growth factor receptors • vascular occlusion/vascular occlusive disease • retina