Effects of erytropoietin treatment and hemodialysis on the serum endothelin level and intraocular pressure of hemodialysis patients.

Aim: The aim of this study is to evaluate the effect of erythropoietin and hemodialysis (HD) on serum Endotheli-1 (ET-1) and intraocular pressure (IOP) levels in HD patients.
Methods: The study group was composed of 34 chronic HD patients undergoing erythropoietin (EPO) treatment, while the control group was composed of 16 chronic HD patients without EPO treatment. Serum samples for measuring levels of ET-1 were taken 1 h before and after HD. Endothelin-1 levels were determined using a commercially available Elisa kit. IOP was measured with a calibrated Goldmann applanation tonometer in the right eyes of patients 1 h before and after HD just after blood samples were taken.
Results: In the EPO group, serum ET-1 levels were significantly higher than those of the control group both before and after HD. Despite increased ET-1 levels in the EPO group, there was no statistically significant difference in pre- and post-dialysis IOP measurements between the erythropoietin and control groups (P > 0.05). In both the HD and control groups, the IOP levels significantly decreased following HD (P < 0.05).
Conclusion: EPO treatment caused an increase in plasma ET-1 concentration compared to the control group, while there was no related increase in IOP with EPO treatment. The role of ET-1 in glaucoma development must involve a mechanism other than increased IOP.