Erythropoietin Over-Expressed in Diabetic Retinopathy
Patients with type 2 diabetes have far higher intravitreal erythropoietin levels than non-diabetics
FRIDAY, Sept. 29 (HealthDay News) -- Intravitreous erythropoietin concentrations are more than 10 times higher in diabetic patients with macular edema than in patients without diabetes, researchers report in the September issue of Diabetes Care.
Cristina Hernandez, M.D., of the Universitat Autonoma de Barcelona in Spain, and colleagues analyzed vitreous samples from 12 patients with type 2 diabetes and diabetic macular edema but no retinal ischemia, and 12 patients with proliferative diabetic retinopathy. The researchers compared them with 10 patients with macular damage but no diabetes. Retinal erythropoietin mRNA expression in eight non-diabetics was compared to erythropoietin mRNA expression in eight retinopathy-free diabetic donors.
The investigators found that patients with proliferative diabetic retinopathy had median intravitreal erythropoietin concentrations of 302 milliunits per milliliter (mU/ml) versus 30 for non-diabetics; diabetic macular edema patients had 430 mU/ml versus 30 for non-diabetics. There were no major differences between patients with diabetic macular edema and proliferative diabetic retinopathy.
"As occurs in proliferative diabetic retinopathy, intravitreous erythropoietin concentrations are strikingly higher in diabetic macular edema," the authors write. "Erythropoietin is expressed in the human retina, and it is upregulated in diabetic patients even without retinopathy. These findings suggest that other factors apart from ischemia are involved in the overexpression of erythropoietin in diabetic retinopathy."