Vitreous levels of erythropoietin in patients with macular oedema secondary to retinal vein occlusions: a comparative study with diabetic macular oedema

Abstract

Objective In a recent study, we found high levels of erythropoietin (EPO) in patients with diabetic macular oedema (DME), suggesting a role of EPO in the pathogenesis of this condition. To investigate a possible relationship between EPO and other diseases causing macular oedema, we determined vitreous levels of this peptide in patients with macular oedema secondary to retinal vein occlusion (RVO) and compared them with levels in patients with DME and control patients. Methods Vitreous and serum samples were obtained from patients with macular oedema secondary to RVO, DME, epiretinal membrane, and macular hole (controls). EPO was measured by radioimmunoassay. Results No differences were found in median vitreous EPO levels between patients with RVO and controls: RVO, 76 mU/ml (30-806) vs controls, 25 mU/ml (10-75) (P ¼ 0.105). Median EPO concentration was higher in DME patients than in patients with RVO or controls: DME, 430 mU/ml (41-3000) vs RVO, 76 mU/ml (30-806) (Po0.0001) vs controls, 25 mU/ml (10-75) (Po0.0001). Conclusions EPO levels are not elevated in patients with macular oedema secondary to RVO. Patients with DME have high levels of EPO. These results suggest that EPO could be involved in the pathogenesis of diabetic retinopathy, but not in macular oedema secondary to RVO.

Neurodegeneration: An early event of diabetic retinopathy

“…However, intravitreal levels of Epo have been found at a similar range in PDR to that in DME (a condition in which hypoxia is not a predominant event) [52] . In addition, intravitreal Epo levels are not elevated in non-diabetic patients with macular edema secondary to retinal vein occlusion [60] . Finally, a higher expression of Epo has been detected in the retinas of diabetic donors at early stages of DR compared to non-diabetic donors and this overexpression is unrelated to mRNA expression of hypoxic inducible factors (HIF-1α and HIF-1β) [53] .…”

Feasibility of intravitreal erythropoietin injections in humans

“…They interpreted the ischaemia-induced, elevated EPO level as a possible endogenous neuroprotective reaction. Garci-Arumi et al 22 found a mean concentration of 25 (range 10 to 75) mU/ml in patients with epiretinal membranes and macular holes and 430 (range 41 to 3000) mU/ml in diabetic macular oedema. Finally, Asensio-Sanchez et al 23 measured 25 (range 5–201) mU/ml in non-ischaemic patients compared with 512 (120 to 880) mU/ml in cases of proliferative diabetic retinopathy.…”

Diabetic Retinopathy: Understanding Pathologic Angiogenesis and Exploring its Treatment Options

“…Its expression, like VEGF expression, is ischemia induced. Its levels are increased in the vitreous of patients with proliferative diabetic retinopathy and diabetic macular edema [84]. However, its actions on angiogenic vascular proliferation seem to be independent of VEGF activity [83,85].…”