Title: Erythropoietin Protein Expression in the Developing Human Eye Shrena Patel, MD^1, Michael Rowe, MS I^1 and Robin K Ohls, MD^1. ^1Pediatrics, University of New Mexico, Albuquerque, NM, United States. Background: Erythropoietin is involved in angiogenesis and may be involved in retinal vascular growth in early human development. A recent study in adult diabetic retinopathy patients revealed significant elevations in vitreal Epo concentrations (N Engl J Med 2005;353:782-92). It is unknown whether Epo plays a similar role in retinopathy of prematurity. We sought to determine if Epo plays a role in normally developing eye, and hypothesized that Epo protein is present in the mid-gestation human fetal eye, and that protein concentrations increase with increasing gestation. Objective: We measured Epo protein concentrations in 12-24 week gestation fetal vitreous and serum. Design/Methods: Fetal serum and vitreous samples were obtained from 12 to 24 weeks gestation. The contents of the globe was extracted, the lens removed, and the aqueous/vitreous collected from both fetal eyes. The retina was isolated and RNA extracted for Epo mRNA determination (in progress). Fetal blood was isolated from the umbilical cord, spun, and serum collected. Samples were stored at -20 C until analyzed by ELISA.
Results:	36 vitreous samples and 18 serum samples between 12 and 24 weeks gestation were collected for measurement of Epo concentrations. At each gestational group measured (12-14, 15-17, 18-20, and 21-24 weeks), Epo concentrations were significantly greater in vitreous than in serum (P<0.01). Epo concentrations also increased with increasing gestation in both vitreous and serum.
Conclusions: Epo concentrations increase with increasing gestational age. Epo concentrations were 2 to 5 fold greater in the vitreous than in the corresponding serum. We speculate that Epo plays an important role in normal retinal vascular development, and that preterm delivery and changes in Epo production adversely affect that development.