Insulin therapy shown to treat early experimental diabetic retinopathy

Researchers presented study results that indicate that subconjunctivally delivered insulin ameliorates degenerative and inflammatory responses in diabetic rat retinas at the Association for Research in Vision and Ophthalmology (ARVO) 2007 Annual Meeting in Fort Lauderdale, Fla.

Regular human insulin in doses ranging from 0.01U to 1U was injected subconjunctivally in control and 1 month diabetic male Sprague Dawley (SD) rats. The biological effects of subconjunctival insulin on the retina were analyzed using immunoblotting, kinase assays and immunohistochemical analysis. Additionally, insulin-loaded hydrogels were designed for subconjunctival implantation to provide low levels of insulin to the retina for prolonged periods. The hydrogels were engineered to be thermoresponsive and hydrolytically degradable, and their pharmacokinetic and pharmacodynamic properties were studied in vitro and in vivo using R28 cells in culture and SD rats respectively.

Lead researcher Ravi S.J. Singh, MD, of the Pennsylvania State College of Medicine in Hershey, Penn., reports that low dose periocular delivery of insulin to the retina of diabetic rats does not alter blood glucose levels and may treat early diabetic retinopathy.