Aqueous humour levels of vascular endothelial growth factor and erythropoietin in patients with diabetic macular oedema before and after intravitreal erythropoietin injection.
To determine the aqueous humour levels of vascular endothelial growth factor (VEGF) and erythropoietin (EPO) in eyes with diabetic macular oedema before and after intravitreal EPO injection. Prospective interventional case series. Eleven eyes of 11 patients with diabetic macular oedema, and 10 eyes of 10 patients with cataract surgery as controls. EPO and VEGF levels in aqueous humour before and after intravitreal EPO injection in patients and compared with controls. Eyes with diabetic macular oedema received an intravitreal injection of EPO (1000 IU/0.05 mL), followed by various intraocular procedures at different intervals (1-54 days) after injection. An aqueous humour sample was obtained and aqueous humour levels of EPO and VEGF were measured using enzyme-linked immunosorbent assay. The aqueous levels of EPO and VEGF were significantly elevated in diabetic macular oedema eyes compared to control eyes (P < 0.05). EPO levels in patients correlated with VEGF levels (r = 0.816, P = 0.002) and central macular thickness at baseline (r = 0.618, P = 0.043). After intravitreal EPO injection, aqueous EPO levels were significantly elevated, whereas aqueous VEGF levels were varied according to the time interval since injection. Visual acuity and central macular thickness were not different after injection, compared to before injection. Aqueous EPO levels did not correlate with serum EPO levels(r = 0.299, P = 0.371). EPO is locally expressed and is correlated with VEGF in eyes with diabetic macular oedema. The role of EPO and the effect of intravitreal EPO in patients with diabetic macular oedema need to be further defined.