Synthetic Hydrogel as an Artificial Vitreous Body. A One-Year Animal Study of Its Effects on the Retina

A hydrogel with a high water content was assessed in vitro and in vivo as a possible vitreous substitute. From a large series of polymers produced by the aqueous polymerization of methyl acrylamidoglycolate methyl ether (MAGME), a gel synthesized in 80% water was selected for an animal study. The gel was injected intravitreally into rabbit eyes and followed clinically by ophthalmoscopy, tonometry, and fundus photography. The gel was clinically well tolerated, but after 6 months ophthalmoscopy revealed progressive pallor of the optic nerve head. The eyes were enucleated one year after injection of polymer. Histopathological examination by light microscopy of retinal and vitreal sections revealed significant retinal disorganization, degeneration of the optic nerve and retinal neural elements, retinal detachment, and inflammatory changes. Analysis of immunohistochemically labeled retinal sections revealed loss of ganglion cells and extensive pathological reaction of the Muller cells and astrocytes. All these findings were consistent with a toxic effect of the polymer itself or some residual contaminants. The cytotoxicity of the hydrogel was assessed in vitro using cultured mouse (Balb/c-3T3) fibroblasts. The bioassay showed both cytostatic and cytocidal effects of the polymer. Our results indicate that hydrogels produced from MAGME monomer cannot function as vitreous substitutes because of severe toxic reaction elicited to the posterior segment of the eye

Proceedings of the Third International Symposium on Retinopathy of Prematurity: An update on ROP from the lab to the nursery (November 2003, Anaheim, California)

The Third International Symposium on Retinopathy of Prematurity (ROP) was convened with the aim of cross fertilizing the horizons of basic and clinical scientists with an interest in the pathogenesis and management of infants with ROP. Ten speakers in the clinical sciences and ten speakers in the basic sciences were recruited on the basis of their research to provide state of the art talks. The meeting was held November 9, 2003 immediately prior to the American Academy of Ophthalmology meeting; scholarships were provided for outreach to developing countries and young investigators. This review contain the summaries of the 20 platform presentations prepared by the authors and the abstracts of presented posters. Each author was asked to encapsulate the current state of understanding, identify areas of controversy, and make recommendations for future research. The basic science presentations included insights into the development of the human retinal vasculature, animal models for ROP, growth factors that affect normal development and ROP, and promising new therapeutic approaches to treating ROP like VEGF targeting, inhibition of proteases, stem cells, ribozymes to silence genes, and gene therapy to deliver antiangiogenic agents. The clinical presentations included new insights into oxygen management, updates on the CRYO-ROP and ETROP studies, visual function in childhood following ROP, the neural retina in ROP, screening for ROP, management of stage 3 and 4 ROP, ROP in the third world, and the complications of ROP in adult life. The meeting resulted in a penetrating exchange between clinicians and basic scientists, which provided great insights for conference attendees. The effect of preterm delivery on the normal cross-talk of neuroretinal and retinal vascular development is a fertile ground for discovering new understanding of the processes involved both in normal development and in retinal neovascular disorders. The meeting also suggested promising potential therapeutic interventions on the horizon for ROP