Study finds lack of VEGF can cause defects similar to dry macular degeneration

Nov 02, 2009

Scientists at Schepens Eye Research Institute have found that when the eye is missing a diffusible form of vascular endothelial growth factor (VEGF), i.e. one that when secreted can reach other cells at a distance, the retina shows defects similar to "dry" macular degeneration, also called geographic atrophy (GA). This finding, published in the November 3, 2009 print edition of PNAS (Proceedings of the National Academy of Sciences), not only increases the understanding of the causes of this blinding disease, but it may also impact the use of anti-VEGF drugs, such as Lucentis, which are designed to neutralize VEGF in eyes with "wet" macular degeneration.

"These results are significant for several reasons. We know little about what causes GA or how to treat it. Our discovery may be an important piece of the puzzle. It shows that reduced VEGF from the retinal pigment epithelium (RPE), RPE, the bottommost layer of the , to the choriocapillaris (CC) - the small beneath retina-- leads to degeneration of the CC. Therefore, the continuous blockage of VEGF may contribute to the development of or a worsening of GA," says Patricia D'Amore, principal investigator of the study and senior scientist at Schepens.

VEGF is a protein that stimulates the growth of new blood vessels. The eye produces several different forms of VEGF that differ in their size and their ability to move away from the producing cell.

Age-related (AMD) is a disease that destroys the macula, the central part of the retina responsible for detailed vision needed for reading, driving and face recognition. It comes in two types—"wet" and "dry." In wet AMD, a pathological overproduction of VEGF leads to the development of abnormal blood vessels, which leak and damage the retina. Wet AMD can be treated with some success with anti-VEGF drugs that block abnormal blood vessel growth and leakage. Dry macular degeneration develops less rapidly, and is related to an accumulation of debris under the retina that can advance to GA where RPE and underlying vessels are lost.

Knowing that the RPE in the adult produced VEGF, the Schepens team hypothesized that in a healthy individual ,the RPE produces forms of VEGF that, when secreted, can move away from the RPE and reach the underlying CC to support its function and survival. The CC vessels are extremely important as they supply the photoreceptors (the light- and color-sensitive cells in the macula) with oxygen and nutrients necessary for vision.

In the PNAS study, the researchers tested their hypothesis using a genetic mouse model in which the RPE produced a form of VEGF that was unable to diffuse. As the mice aged, they began to display an age-dependent degeneration of both the CC and RPE, culminating with the death of photoreceptors and vision loss, similar to that observed in GA,.

The next step in the research, according to the first author Dr. Magali Saint-Geniez, is to determine if this model can be used to investigate the role of RPE-CC interaction in AMD and to design new therapies.

Source: Schepens Eye Research Institute

Explore further: US scientists make embryonic stem cells from adult skin

add to favorites email to friend print save as pdf

Related Stories

Study suggests new approach to common cause of blindness

Jun 14, 2009

Researchers at the University of North Carolina at Chapel Hill School of Medicine in collaboration with lead investigators at the University of Kentucky have identified a new target for the diagnosis and treatment of age-related ...

Recommended for you

Leeches help save woman's ear after pit bull mauling

Apr 18, 2014

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

New pain relief targets discovered

Apr 17, 2014

Scientists have identified new pain relief targets that could be used to provide relief from chemotherapy-induced pain. BBSRC-funded researchers at King's College London made the discovery when researching ...

User comments : 0

More news stories

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Study says we're over the hill at 24

(Medical Xpress)—It's a hard pill to swallow, but if you're over 24 years of age you've already reached your peak in terms of your cognitive motor performance, according to a new Simon Fraser University study.

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.