Retinitis pigmentosa (RP) is a rare genetic disorder that leads to the gradual degeneration of photoreceptors, the light-sensitive cells in the retina, ultimately causing vision loss. Currently, there is no cure for this devastating condition. However, researchers at the National Institutes of Health (NIH) have made a significant breakthrough that could change the future of treating RP and other degenerative retinal diseases. Their innovative eye drops, which contain a tiny fragment of a natural protein found in the eye, have successfully extended vision in animal models of RP.
The eye drops feature a short segment of pigment epithelium-derived factor (PEDF), a protein that plays a vital role in protecting the retina’s fragile cells. PEDF is naturally produced in the eye and has been shown to help sustain retinal health. While these eye drops aren’t a cure, the study’s findings represent a promising step forward in slowing the progression of retinal degeneration.
“Although these drops aren’t a cure, they show that PEDF-based eye drops can slow down the progression of degenerative retinal diseases like retinitis pigmentosa and dry age-related macular degeneration (AMD),” said Patricia Becerra, Ph.D., the senior author of the study and Chief of the NIH’s Section on Protein Structure and Function at the National Eye Institute. “The next step is human clinical trials, and we’re excited to begin.”
The research directly addresses a central challenge in treating degenerative retinal diseases: cellular stress. Conditions like RP and AMD stem from genetic mutations and other factors that cause retinal cells to become damaged, lose their function, and eventually die. This leads to photoreceptor loss, vision impairment, and, in many cases, blindness.
Previous studies from Dr. Becerra’s lab found that PEDF had protective effects on retinal cells but struggled to penetrate the outer layers of the eye. In order to overcome this barrier, her team developed short peptides—tiny fragments derived from the PEDF protein. These peptides were designed to not only preserve retinal cells but also be small enough to reach the retina efficiently when delivered as eye drops.
The research, led by Alexandra Bernardo-Colón, tested two peptide-based formulations, “17-mer” and H105A. Both formulations proved effective in animal models, with the peptides reaching the retina within an hour of application and remaining active for up to 48 hours without causing harmful side effects.
In tests with H105A eye drops, mice treated daily with the peptide preserved up to 75% of their photoreceptor cells, while placebo-treated mice lost nearly all of their photoreceptors within a week.
“For the first time, we show that these peptide eye drops can actually reach the retina and have a therapeutic impact,” said Bernardo-Colón. “The results are dramatic—healthier retinas with no adverse effects.”
While gene therapy is being developed for specific retinal diseases, including RP, these peptide-based eye drops could serve as a critical interim treatment for patients. By preserving retinal cells, the drops could help maintain vision until more advanced therapies are ready.
The research team also tested how the preserved retinal cells responded to gene therapy in mouse models. The results were promising, with treated mice maintaining their vision for an additional six months after receiving gene therapy.
To further validate the potential of these peptides for human use, the research team collaborated with Natalia Vergara, Ph.D., at the University of Colorado Anschutz to test the peptides on human retina-like tissues grown in the lab. When exposed to stress, untreated tissues quickly died, while tissues treated with the peptides remained viable and healthy. This crucial step marks a promising advance toward human clinical trials.
The success of these eye drops in animal models and human tissue tests offers a new, hopeful path for treating retinal degenerative diseases. While this approach is still in its early stages, the results are encouraging. In the future, these peptide-based eye drops could not only slow the progression of RP and AMD but also offer a bridge to more effective, permanent treatments, such as gene therapy.
With human clinical trials on the horizon, the research team at the NIH is one step closer to making a significant impact in the lives of millions affected by degenerative eye diseases.
By Impact Lab
