Nerve Regrowth Breakthrough Could Offer Hope for Blindness Treatment
Researchers at the University of Connecticut have uncovered promising findings that may pave the way for treating a common cause of blindness. The study, published in the September issue of Experimental Neurology, demonstrates how injured optic nerves in mice can regrow toward the brain when treated with an injectable peptide.
This breakthrough could have significant implications for treating vision loss caused by blunt trauma and glaucoma, the second leading cause of blindness worldwide, according to the CDC.
Understanding Optic Nerve Damage
Blunt trauma, such as from car accidents, and glaucoma can severely damage the optic nerve. This damage typically leads to permanent vision loss, as severed nerves rarely regenerate.
However, recent research from Ephraim Trakhtenberg, PhD, and his team at the UConn School of Medicine suggests otherwise. The study involved contributions from:
• Agnieszka Lukomska, now a professor at the University of Warsaw.
• Bruce Rheaume, a physician-resident at Dartmouth Medical Center.
• Matthew Frost, a PhD candidate at UConn.
Injectable Peptide Stimulates Nerve Regrowth
The team used a peptide, a small fragment of a larger protein, to stimulate nerve regrowth in mice with injured optic nerves. Key findings include:
• Dense regrowth through the injury site within six weeks.
• Nerve fibers extending all the way to the optic chiasm, the brain region where the optic nerve first connects.
The optic chiasm plays a vital role in processing light and regulating circadian rhythms.
Dr. Trakhtenberg noted that longer trials, spanning at least three months, are necessary to determine if the regenerated fibers can reach brain areas responsible for vision restoration.
How Peptides Unlock Regenerative Potential
The approach stemmed from earlier research showing that severe inflammation could induce limited nerve regrowth. While inflammation is not a viable treatment option for humans, it inspired the team to investigate the mechanisms behind it.
The Role of Fibronectin
• Inflammation draws immune cells, such as macrophages, which secrete a protein called fibronectin.
• Fibronectin encourages nerve cells to regrow, but levels around injured nerves are usually too low to be effective.
To overcome this, the team synthesized peptides derived from fibronectin, which are small enough to inject directly into the eye. These peptides effectively replicated fibronectin's nerve-regenerating properties.
Promising Results
The fibronectin peptide injections yielded dramatic outcomes:
• Improved survival of nerve cells in injured optic nerves.
• Significant regrowth of nerve fibers through the injury site and toward the optic chiasm.
Gene therapy combined with peptide injections further enhanced regrowth, but peptides alone also produced strong results.
Dr. Trakhtenberg highlighted the potential for clinical application:
“One of the highlights is that the peptide is just a piece of protein. You can inject it. That gives it a therapeutic potential for clinical trials as a treatment.”
Next Steps in Research
The team plans to conduct longer trials in mice to evaluate:
1. How far the regenerated nerves can grow beyond the optic chiasm.
2. Whether the regrowth eventually restores visual function by reaching brain regions responsible for sight.
3. The effectiveness of combining the peptide with other treatments to optimize regrowth.
A Hopeful Outlook
This groundbreaking research represents a potential shift in treating optic nerve injuries caused by trauma or glaucoma. With continued investigation and eventual clinical trials, fibronectin-derived peptides may one day offer a viable therapy to restore vision for millions of patients worldwide.
Resource:
Agnieszka Lukomska et al, Augmenting fibronectin levels in injured adult CNS promotes axon regeneration in vivo, Experimental Neurology (2024). https://www.sciencedirect.com/science/article/abs/pii/S0014488624002036?via%3Dihub
