Promising New Eye Drops Could Slow Down Retinitis Pigmentosa

New Eye Drops Show Promise in Slowing Vision Loss in Animal Models of Retinitis Pigmentosa

In a groundbreaking development, researchers at the National Institutes of Health (NIH) have created a novel form of eye drops that could slow vision loss in animal models of inherited degenerative diseases, particularly retinitis pigmentosa (RP). This discovery offers hope for patients suffering from this condition, which causes progressive vision loss and often leads to blindness. The eye drops contain a small fragment derived from a naturally occurring protein called pigment epithelium-derived factor (PEDF), a protein found in the eye that helps protect retinal cells from damage. Though not a cure, the findings represent a significant step forward in understanding and potentially treating various retinal degenerative diseases.

Understanding Retinitis Pigmentosa and Other Degenerative Retinal Diseases

Retinitis pigmentosa is a group of inherited eye diseases that cause the gradual breakdown of photoreceptor cells in the retina, leading to progressive vision loss. These diseases often begin in childhood and can continue to deteriorate over many years, eventually causing blindness. Despite advances in genetics and gene therapy, there remains a pressing need for effective treatments that can slow down or halt the progression of these diseases.

All degenerative retinal diseases, including RP and age-related macular degeneration (AMD), share a common underlying factor—cellular stress. Cellular stress, often triggered by genetic mutations or environmental factors, leads to the dysfunction and eventual death of retinal cells, particularly the photoreceptors that are responsible for capturing light and transmitting visual information to the brain.

In response to this, researchers have been investigating ways to protect and preserve retinal cells in order to delay vision loss. A recent study from the NIH offers a promising solution by using PEDF-based eye drops to slow the progression of retinal degeneration in animal models.

PEDF: A Key Player in Protecting Retinal Cells

The protein pigment epithelium-derived factor (PEDF) has long been known for its protective properties in the eye. PEDF helps maintain the health and function of retinal cells by reducing cellular stress, a key factor in retinal degeneration. However, despite its potential, the full PEDF protein is too large to effectively reach the retina when administered topically, and it also has other functions in retinal tissue that make it difficult to use directly as a treatment.

To overcome these challenges, researchers developed a solution using short peptides derived from PEDF. These peptides are small enough to penetrate the eye's outer layers and reach the retina, where they can interact with PEDF receptor proteins on the surface of retinal cells. By targeting specific areas of the PEDF protein that support cell viability, these peptides can preserve retinal cells and reduce the damage caused by cellular stress.

Promising Results in Animal Models

In the study, researchers tested two different PEDF-derived peptides in eye drop formulations. The first peptide, called "17-mer," contains 17 amino acids from the active region of PEDF. The second peptide, "H105A," is similar but has a stronger binding affinity for the PEDF receptor, which may enhance its therapeutic effects. Both peptides were tested in animal models, specifically mice with retinitis pigmentosa-like disease.

When administered once daily to young mice with retinal degeneration, the H105A peptide slowed the degeneration of photoreceptors and preserved vision. The results were remarkable: after a one-week treatment, mice treated with the H105A peptide retained up to 75% of their photoreceptor cells and continued to respond to light, while the control mice that received a placebo had almost no remaining photoreceptors and minimal retinal function. The eye drops were also found to be non-toxic, with no adverse effects on the animals' health.

A Step Toward Human Trials

The success of the PEDF-derived eye drops in animal models has opened the door for future clinical trials in humans. However, before testing in human patients, the researchers wanted to ensure the peptides would be effective in human retinal cells as well. To do this, they collaborated with scientists to test the peptides in a human retinal tissue model. When human retinal cells grown in a dish were exposed to chemicals that induced cellular stress, the peptides were able to protect the cells, preventing them from dying. This is a crucial step in validating the efficacy of the treatment in humans, as the retina of different species can respond differently to treatment.

Given these promising results, the researchers are now preparing to test the PEDF-derived eye drops in human clinical trials. If successful, these eye drops could serve as a valuable tool for preserving vision in patients with retinitis pigmentosa and potentially other retinal diseases, bridging the gap until gene therapies and other treatments are more widely available.

Combining Gene Therapy and PEDF-Derived Peptides

One exciting aspect of this research is the potential for combining PEDF-derived peptide eye drops with gene therapy. In collaboration with international researchers, the team tested whether gene therapy could be more effective when combined with the eye drop treatment. The results were promising: when mice were treated with gene therapy after using the eye drops, their vision was preserved for an additional six months. This combination of therapies could offer a comprehensive approach to treating retinal degeneration, preserving photoreceptors long enough for gene therapy or other treatments to take effect.

Conclusion: A New Hope for Retinal Degeneration

The development of PEDF-derived eye drops represents a significant step forward in the fight against retinal degenerative diseases such as retinitis pigmentosa. While these drops are not a cure, they offer a potential treatment to slow the progression of these diseases and preserve vision in affected individuals. As researchers continue to explore the effectiveness of these eye drops in human trials, there is hope that this treatment could become a vital tool in the management of retinal degenerative conditions, improving the quality of life for countless individuals and providing a bridge to more advanced therapies.

Learn more: https://www.nature.com/articles/s43856-025-00789-8