Study of erythropoietin and erythrocyte enzymes role in diabetic retinopathy

We studied in 42 diabetics with and without retinopathy, and in 44 controls the role of erythropoietin (EPO) and its relationship with two erythrocyte enzymes, the methemoglobin reductase (MHR) and low molecular weight acid phosphatase (ACP1). Serum EPO (mIU/ml), was determined by ELISA. MHR (mmol/gHb/min) and ACP1 (mu mol/gHb/h) activities, by spectrophotometry. EPO showed a trend for an increase in diabetics, and in the retinopathy group. ACP1 and MHR activities were also higher in diabetics compared to the controls (360.99 +/- 141.81 vs 188.63 +/- 43.17, p < 0.001 and 22.73 +/- 8.48 vs 14.526 +/- 3.863, p < 0,001, respectively). EPO was correlated with ACP1 (p = 0.005; r = 0.565) and with MHR (p = 0.007; r = 0.545), enzymes correlated with each other (p = 0,002; r = 0.600), in diabetics without retinopathy, suggesting that this group was more protected from retinopathy. Other mechanisms may also be involved in this protective process.