Increasing Blood Vessel Permeability to Get Treatments to the Retina

January 15, 2013

A Foundation-funded research team from the Johns Hopkins School of Medicine has identified a technique that may someday enable vision-saving therapies to more effectively penetrate the retina. Led by Dr. Jeremy Nathans, the team found that reducing the levels of two proteins, Frizzled4 and Norrin, increases retinal blood vessel permeability, which eventually could provide better diffusion of future treatments. The discovery was made in a mouse study and reported in a recent issue of the journal Cell.

Blood vessels in a healthy outer retina form what is known as the blood-retina barrier to protect the eye from infections and harmful substances. However, the barrier also prevents many drugs and therapies — especially those comprised of large molecules — from getting inside the eye. Temporarily weakening the barrier might provide an opportunistic window for delivering treatments to the retina and inner regions of the eye.

Dr. Nathans indicated that further studies of Frizzled4 and Norrin may reveal new ways to decrease retinal permeability to treat prevalent conditions such as wet age-related macular degeneration and diabetic retinopathy, which are caused by leaky blood vessels.

“This is important work by Dr. Nathans and his colleagues, says Dr. Stephen Rose, chief research officer, Foundation Fighting Blindness. “Being able to control the retina’s vasculature may be a powerful way to efficiently deliver drugs and therapies for a variety of retinal diseases. This isn’t something quite ready to be studied in humans, but it is important that we drive this kind of basic research to come up with new and better approaches to saving vision.”