--Prevents Damage from Diabetic Retinopathy, Macular Degeneration
Scientists at Johns Hopkins and Novartis Ltd. Pharmaceuticals, in partnership with Novartis' CIBA Vision eye care unit, have identified a drug that completely stops the growth of abnormal blood vessels on or beneath the retinas of laboratory mice.
Results of the mouse studies, published in the June issue of the American Journal of Pathology, could mean that people at risk for blindness associated with macular degeneration or diabetes may one day be able to pop a pill to prevent blinding blood vessel growth. Vessels that grow abnormally in the eyes can leak fluid or blood, causing rapid and severe vision loss. Such growth is the hallmark of diabetic retinopathy and age-related macular degeneration, the leading causes of blindness in young and old people, respectively, in developed countries.
Human trials of the drug, called PKC 412, could begin early next year, says Peter A. Campochiaro, M.D., senior author of the study and a professor of ophthalmology and neuroscience at Hopkins.
"This is the first drug I've seen that has a knock-your-socks-off kind of effect," Campochiaro says. "Previous drug studies have only halted growth of abnormal vessels by roughly 50 percent, but this medication appears to stop it completely in three mouse models. Remarkably, the drug can be given orally, the preferred method of drug delivery in people. If these animal models are predictive, the drug should work in people."
In diabetics, high blood sugar through a cascade of events can lead to
damage to normal retinal blood vessels and a decrease in the supply of oxygen
and nutrients. The retina calls for back up by releasing vascular endothelial
growth factor (VEGF), a substance that stimulates new blood vessels to grow to
try to compensate. However, the back-up blood vessels generally are faulty;
they leak, bleed and encourage scar tissue th
Contact: Karen Infeld
Johns Hopkins Medical Institutions