The Eyes Have It: New Views of Age-Related Macular Degeneration

close up of senior woman face and eye

(DGIwire) – Advanced neovascular or “wet” age-related macular degeneration (AMD) is a leading cause of vision loss among people age 50 and older, according to the National Eye Institute, a division of the National Institutes of Health. According to a recent report in Nature Medicine, researchers at Boston Children’s Hospital have now proposed a new idea that could potentially change how doctors approach the disease.

Wet AMD is caused by the growth of abnormal blood vessels behind the retina. According to a news release from Boston Children’s Hospital, the researchers have suggested another cause: dysfunctional energy metabolism in the eye that starves the retina’s light receptors of fuel. Based on their observations, the researchers believe it may be possible to use drugs to help photoreceptors take in nutrients, and that this could be a new avenue to treating diseases like AMD.

This finding comes on the heels of an international study of 43,000 people, reported in Nature Genetics, that significantly expands the number of genetic factors known to play a role in AMD. Up to this point, researchers had identified 21 regions of the human genome—called loci—that influence the risk of AMD. The new research, according to the NIH, brings the number up to 34. The NIH reported in a news release that the findings may help improve the understanding of the biological processes that lead to AMD and identify new therapeutic targets for potential drug development.

“New discovery and research for AMD is pushing back the frontiers of our understanding of this disease,” said Dr. Geert Cauwenbergh, President and CEO of RXi Pharmaceuticals. “Some of this research is focused on the proteins that trigger subretinal fibrosis in wet AMD that may cause irreversible retinal scarring, often a secondary component of this later stage disease. What if we could regulate or block these proteins in the first place?”

RXi Pharmaceuticals is showing how this approach could be possible. Here’s how it works. We all learned “DNA codes for RNA codes for proteins” in school. Dr. Mello has shown in his Nobel Prize winning research how a naturally occurring phenomenon called RNA interference—“RNAi” for short— can target and destroy specific RNAs before they can serve as templates for the generation of 100s to 1000s copies of the coded protein. The theory is, “Reduced scar proteins, reduced retinal scarring.” The company has developed a therapeutic platform of self-delivering RNAi compounds, called sd-rxRNA®. The first of these compounds, RXI-109, is in development to target connective tissue growth factor (CTGF), a key regulator of scar formation in the eye and skin.

The company is conducting an ongoing Phase 1/2 clinical trial in patients with wet AMD to evaluate the safety and clinical activity of RXI-109 to prevent the progression of retinal scarring. “By concentrating on how RNA-based therapeutics can influence protein production in the retina, we can target the harmful scarring component of this disease,” added Dr. Cauwenbergh.

If successful, the treatment could potentially preserve vision for a longer time and may benefit patients with other eye diseases involving scarring, such as proliferative vitreoretinopathy and proliferative diabetic retinopathy.