Tolerance and safety of ocular use of recombinant human erythropoietin (rhEPO). Neuroprotective effects in ocular hypertension/glaucoma

Abstract

Abstract Purpose The purpose of this study was to evaluate the long‐term effects of monthly intravitreal injections of rhEPO in a rabbit model. Methods Sixteen New Zealand rabbits were divided into 4 groups: control (no injection), saline injection, or rhEPO injections of 500 U and 1000 U (N=4 per group). The right eye of each animal was injected monthly over a period of 7 months. Fundus examination and electroretinography (ERG) were performed at 1 day prior, and 1 week, 1 month, and 6 months after the initial injection. After the final ERG, animals underwent fluorescein angiography and sacrifice one week later. Scotopic and photopic ERG amplitude and implicit times were analyzed by calculating a ratio between the right and the left eyes. Angiograms were graded for the presence of neovascularization or leakage. Statistical analysis was carried out using two‐way ANOVA. Results Fifteen animals were used for this experiment (1 developed a traumatic cataract and was excluded). Between all groups and time points, there were no statistically significant differences in the computed right eye:left eye ratios for the scotopic or photopic ERG components (p>0.05). No evidence of neovascularization or fluorescein leakage was seen on angiography. There were no visible differences in retinal architecture or thickness in the rhEPO groups when compared to uninjected controls. Conclusion Monthly 0.1 ml intravitreal injections of rhEPO at a dose of up to 1000 U over 7 months is well‐tolerated and does not cause adverse effects on retinal function, architecture, or vasculature in a rabbit model. A review of published data on rhEPO and Glaucoma will also be presented.