Now in the their sixth year of a National Institutes of Health study on the use of protease inhibitors, UNM Health Sciences researchers have made significant progress in developing an effective pharmacological approach to the most common cause of blindness in diabetic patients.

Arup Das, M.D., Ph.D., division chief for Ophthalmology and an associate professor in the UNM Department of Surgery, and Paul McGuire, PhD, professor of Cell Biology and Physiology, have focused much of their work on using protease inhibitors to slow the growth of new blood vessels in the eyes. Proteases are enzymes that help break down existing blood vessels enabling new vessels to grow.

According to the National Diabetes Data group, the risk of ocular diseases in diabetics is 25 times that of the general population, with the most common cause of loss of vision being diabetic retinopathy, a condition where tiny blood vessels inside the retina the light-sensitive tissue at the back of the eye are damaged and bleed. According to the National Institutes of Health, 90 percent of Type I (younger onset) diabetics and 65 percent of Type II (adult onset) diabetics will develop retinopathy within 10 years after developing diabetes. In New Mexico, more than 37,000 people have been diagnosed with diabetic retinopathy.

According to Das, when the retina in the eye suffers damage due to poor circulation or ischemia, the body produces new blood vessels to restore oxygen and nutrition supply. The growth of these new blood vessels is called angiogenesis. If these fragile retinal vessels break down or leak, they can result in severe hemorrhage with vision impairment and blindness. Currently, the most common treatment is to destroy the new vessels with a laser. "This approach is effective in preserving central vision in about 80 percent of patients, but it usually destroys the patient's peripheral vision," said Das. "The result is that the patient's vision at night and in low-light conditions is also impaired."

Das and McGuire received a National Institutes of Health grant in 1997 to begin studying non-surgical alternatives for the treatment of angiogenesis and prevent blindness. Based on their pre-clinical work in the lab, Angstrom Pharmaceuticals has completed a Phase One trial of a protease inhibitor they believe will provide a viable alternative to laser surgery. However, the inhibitor will be tested in clinical trials in patients with another vision threatening condition, macular degeneration.

Using drug therapy to treat retinopathy will minimize tissue damage and eliminate side effects associated with laser therapy. A pharmacological approach will also provide alternative delivery methods, including oral drugs and eye drops. The team believes that in addition to providing a more effective treatment, these new delivery options will attract more people to seek treatment.


Contact: Cindy Foster, 272-3322