Evidence for the Involvement of the Ephrin/Eph System in Angioproliferative Ocular Diseases
Agostini H. T., Gogaki E., Maier P., Blinova E., Martin G., Hansen L. L.
Dept. of Ophthalmology, University Freiburg
Purpose: Ephrines and their Eph receptors are known to control axonal guidance. Both, receptors and ligands, are membrane bound and help to coordinate the cell-cell interaction. In the eye, ephrins are involved in retino-tectal projection. There is increasing evidence, that this receptor-ligand system contributes to angiogenesis. Arteries and veins show a specific pattern of Ephrin/Eph expression.
Method: a) Retinal pigment epithelium (RPE) was cultivated from surgically removed subretinal membranes (CNV) in patients with age related macular degeneration (AMD). Differences in the expression of angiomodulatory factors in comparison to control RPE were investigated on the RNA and protein level. b) Changes in physiological vascular development of the retina and oxygen induced angioproliferative retinopathy were quantified after intravitreal injection of dimeric EphB4 and Ephrin B2 in the mouse.
Results: a) RPE from CNV-membranes express the receptor EphA7 while control RPE does not. Cloning and sequencing of the complet EphA7 mRNA showed that the EphA7-gene is transcribed completely. b) Intravitreal injection of dimeric EphB4 and Ephrin B2 leads to increased vascular proliferation in the mouse model for oxygen induced retinopathy. The physiological vascular development of the retina showed only minor changes.
Conclusions: In the eye, the Ephrin
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