Broccoli and Vision: A Surprising Connection


(DGIwire) – Carrots are supposedly beneficial for eyesight but—broccoli? Researchers from the Buck Institute for Research on Aging, located in Novato, CA, recently boosted the potency of a broccoli-related compound by 10 times and identified it as a possible treatment for age-related macular degeneration (AMD), a leading cause of vision loss affecting more than two million Americans, according to the National Eye Institute.

As the Buck Institute researchers reported in the journal Scientific Reports, the compound in broccoli that prompted the inquiry is indole-3-carbinol (I3C). According to the Buck Institute, I3C helps clear cells of environmental toxins by activating a specific protein—the aryl hydrocarbon receptor (AhR), which upregulates pathways involved in chemical detoxification. Previous studies suggest that AhR-deficient mice develop a condition that looks extremely similar to AMD.

The Buck Institute researchers acknowledge that people would need to eat an unreasonable amount of broccoli and other cruciferous vegetables to get enough of a protective effect to impact AMD, but suggest it is worth capitalizing on nature’s wisdom to find related molecules that can deliver therapeutic benefit.

Research taking place elsewhere is focused on the proteins that trigger the process in wet AMD—characterized by the growth of abnormal blood vessels from underneath the macula. Current therapy targets VEGF, vascular endothelial growth factor, to reduce the growth of these blood vessels. Even so, irreversible retinal scarring is often a secondary component of this later-stage disease. The goal now is to see if it is possible to regulate or block these proteins that cause the scarring in the first place.

“As more is learned about the mechanisms behind wet AMD, new therapies may become available to help those grappling with the vision loss it can bring,” says Dr. Geert Cauwenbergh, President and CEO of RXi Pharmaceuticals. “We are showing how this approach could be possible.”

It has been shown that 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.” RXi 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.

RXi 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.

“Improved treatment for AMD is likely to be the result of innovative approaches using what we have learned so far about how the overexpression of certain proteins impact eye health,” Dr. Cauwenbergh adds.