Dry AMD treatment: diabetics may escape PDR

Proven Arthritis Drug Shows Promise versus Dry AMD:

While ophthalmologists can turn to several medications for patients with vision-threatening “wet” age-related macular degeneration (AMD), there are no effective treatments for advanced “dry” AMD, the more common form.

Today a research group led by Jason S. Slakter, MD, New York University School of Medicine, reports on a phase-two clinical trial of fenretinide, a synthetic derivative of vitamin A.

Risk of developing wet AMD decreased almost two-fold in dry AMD patients who took the medication. Geographic atrophy (GA) lesion growth was also reduced in the fenretinide group.

This reduced growth correlated with lowered blood levels of the biomarker retinol binding protein (RBP) — an indication that fenretinide was working. Patients whose RBP decreased 60 percent or more also had the most significant reductions in lesion growth.

GA lesions degrade the area of the eye called the retinal pigment epithelium (RPE), which can result in significant vision loss.

Advanced AMD, in either wet or dry form, can destroy the detailed, central vision we need to recognize faces, read, drive, and enjoy daily life. It is a major cause of vision loss in the United States.

In the advanced wet form abnormal new blood vessels develop under the retina, then bleed or leak fluid and form scars. Advanced dry AMD sometimes abruptly converts to the wet form.

Fenretinide works on three key AMD disease mechanisms: it has strong anti-inflammatory properties, inhibits abnormal blood vessel growth (angiogenesis) and reduces vitamin-A derived toxins such as A2E and lipofuscin. These toxins accumulate in the RPE and interfere with its ability to nourish light-receptor cells in the retina.

“Evidence from our study and others points to fenretinide’s potential to treat and prevent diseases of the retina,” Dr. Slakter said.

Visit the American Opthamology Academy’s Web site at www.aao.org

Leading cause of blindness identified - Age-related macular degeneration (AMD)

The mechanism behind a leading cause of blindness has been discovered, which could result in new treatments for a disease that causes 50 per cent of all blindness in the western world.

Age-related macular degeneration (AMD) is caused by damage to the macula – part of the retina at the back of the eye – and is thought to be linked to alterations in the gene resonsible for CFH, a protein involved in the body's immune response.

To work out how this might cause AMD, Paul Bishop at the University of Manchester, UK, and colleagues applied normal and diseased forms of CFH to macula obtained from donated eyes. Abnormal CFH seemed unable to bind to the macula, probably as a result of not being able to bind to two specific carbohydrates.

If there is not enough functional CFH bound to the macula, the immune system does not recognise the tissue as its own and so will attack it, says Bishop. "Now that we know the mechanism, we can think about treatments, such as injecting CHF into the bloodstream."