SCIENCE / EYE DISEASE : Protein Identified as Key Agent in Forms of Blindness
Ending a 45-year search for the secret to the major causes of blindness, Boston researchers have identified a protein that causes loss of vision from several eye diseases, including diabetic retinopathy, which strikes as many as 50,000 Americans annually.
Previous research has shown that the activity of this protein can be blocked in the laboratory, offering the hope for the first effective treatments of these diseases, which also include retinopathy of prematurity and age-related macular degeneration.
The protein, called vascular endothelial growth factor (VEGF), causes the proliferation of blood vessels in the eye in response to diabetes and other disorders, the team reported this week in the American Journal of Pathology. The vessels and blood leaked from them cause loss of vision.
Although the latest discovery was made in monkeys, unpublished work from this team and other researchers strongly suggests that the protein plays a crucial role in humans as well.
“This is a terrific piece of work,” said Dr. Martin Wand, a Hartford, Conn., ophthalmologist who is familiar with the research. “If we can specifically counter this key agent, we might be able to use it for literally dozens and dozens of diseases” in which proliferation of blood vessels plays a role.
“This is the best candidate that has come along in years,” said Dr. Lloyd Paul Aiello of the Joslin Diabetes Clinic in Boston, who was not involved in the research. “Other factors are also probably involved, but this appears to be the major (cause) of the disease.”
The research looks very promising, said Dr. Bradley Straatsma of UCLA’s Jules Stein Eye Research Institute. “As we learn more and more about it, we’ll be in a better position to judge exactly how this helps us in the management of patients.”
Diabetic retinopathy, a complication of diabetes, is the leading cause of blindness among adults between the ages of 25 and 64. Age-related macular degeneration is the leading cause of blindness over age 65.
Retinopathy of prematurity is much less common, but is considered more tragic because it occurs at the onset of life. It appears most often in premature infants receiving oxygen in an incubator.
In all three diseases, and many rarer ones as well, blood vessels proliferate in the eye. Their physical presence, as well as blood that leaks out of them, block the flow of light to the retina. Now, the best treatment for diabetic retinopathy involves the use of a laser to destroy some of the retinal cells from which new blood vessels arise, thereby inhibiting further growth. But it is not 100% effective and causes some damage on its own.
The new studies were conducted by Dr. Anthony Adamis and Dr. Joan Miller of the Massachusetts Eye and Ear Infirmary in Boston.
