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Research into Nerve Growth Factor for Glaucoma Offers New Hope for Treatment

Posted on November 08, 2016 by Glaucoma Research Foundation

When the eye doctor tells Sarah she has glaucoma, it's a shock. Sarah hadn't even suspected a problem -- she only went to the doctor for a normal vision exam. Her diagnosis results in weeks spent struggling with suffocating anxiety every time she thinks about the possibility of losing her vision -- and along with it her career as an artist.

She begins using eye drop medication prescribed by her doctor to keep intraocular pressure under control, because lowering eye pressure is currently the only treatment option for glaucoma patients. But this will not always be the only option. Researchers have hope for future treatments. Exhilarating advances in the amazing field of optic nerve protection and regeneration will one day lead to treatments that stop optic nerves from dying and even coax reluctant nerves back to life.

Where Does Glaucoma Treatment Stand Today?

Even if you don't have glaucoma, it's easy to close your eyes and imagine living with the slow relentless loss of vision as the disease gradually damages the optic nerve. The only way to prevent this deterioration is to get an early diagnosis and proper treatment -- but even with the best treatment to manage pressure, some patients still lose vision.

Like termites munching away deep inside your house, glaucoma stays hidden while doing damage, to cells in the optic nerve little by little. By the time slight changes in vision are noticeable, the injury is permanent.

At this stage, treatment may stop ongoing nerve damage, but even when medication keeps intraocular pressure under control, optic nerve cells can continue to die.1 Finding treatments that do more than manage eye pressure and that will eventually reverse blindness is just one goal that motivates researchers.

The field of glaucoma research is bursting with fresh discoveries. Every study that's published on glaucoma -- at least 1,200 of them from January to September 2016 -- expands the field and takes another baby step towards new treatment. Each study demands significant time and dedication, but such efforts pay off when results reveal another piece of information about connections between the optic nerve and the brain, genetic activity specific to glaucoma, or clues leading to the possibility of drugs that trigger nerve regeneration. Even though the central nervous system isn't equipped to fix damaged nerve cells, future treatments may offer some assistance.

Exploring Nerve Regeneration and Neuroprotection

Nerve regeneration focuses on ways to regrow nerves. Neuroprotection is all about preventing the death of nerve cells. Treatments that achieve both goals must be developed before vision loss due to glaucoma can be stopped or reversed. The good news is that such treatments are on the horizon, thanks to a family of proteins called neurotrophic factors that regulate the growth and survival of nerves.

Many neurotrophic factors are hard at work throughout the human body, but a group of progressive researchers at Harvard Medical School took one of those steps forward when they targeted several factors that are actively involved in the optic nerve.

One of the researchers, Zhigang He, PhD, was looking for ways to regenerate nerve fibers in patients with spinal cord injuries. He used the optic nerve as a model for his research. In the process, he learned that the nerve grew when he used a combination of growth-promoting genes and substances to block natural growth inhibitors. Meanwhile, one of his colleagues, Larry Benowitz, PhD, had success using substances that promoted nerve regeneration.

As He, Benowitz and twelve other experts at Harvard worked together, they ultimately landed on a mixture of three growth factors -- ciliary neurotrophic factor, insulin-like growth factor 1 and osteopontin -- that successfully regenerated optic nerves in experimental models.2 But researchers were faced with another major challenge when the revitalized nerves couldn't yet carry the vision-producing signal from the eye all the way to the brain.

They kept searching until they found the problem. It turned out that damaged nerves lose myelin, which is a coating around nerves that helps conduct and speed up nerve impulses. So they added a potassium channel blocker known to strengthen nerve signals when myelin is missing to the mix.3

Of course, they're not the only ones studying nerve growth factor. Just one prime example comes from Jeffrey L. Goldberg, MD, PhD, at the Byers Eye Institute at Stanford University School of Medicine and a member of the research consortium, Catalyst for a Cure, who began testing ciliary neurotrophic factor. In patients with glaucoma, this particular neurotrophin shows special promise for regeneration and neuroprotection.

Research Into Nerve Growth Factor Demands Dedication

The breakthroughs achieved by these researchers make it sound like success in glaucoma research comes easy. The truth is that one small advance takes years of effort and many experts working together to conquer the exquisite complexity of the central nervous system. For starters, they have to overcome the central nervous system's natural tendency to stop nerves from regenerating, a protective mechanism designed to maintain organization and function.

Researchers must experiment with many different nerve growth factors to determine which combination of factors might work. They have to determine how much of each factor to use because nerve cells die without the precise amount. Then they have to find the best way to introduce growth factors to a microscopic point in the eye in order to move results from the laboratory to the clinic.

When they're finally successful with one goal, the same work must be refined and duplicated to prove that it consistently achieves the same results, which takes more years of meticulous work. And all of this is accomplished in the lab because there must be no doubt about safety and effectiveness before potential treatments can move forward into human clinical trials.

Research is a long, tedious process, but glaucoma experts tirelessly push forward because every success brings them closer to restoring vision. Here's the thing -- they don't just face challenges in the lab, they also constantly deal with budget shortages. They can't keep making progress without your financial support.

Together We Can Stop the Progression of Glaucoma

Take a look at Glaucoma Research Foundation's strategic goals and you'll see that the first item on the list says “to protect and restore the optic nerve.” There's no doubt that this is the way to stop progressive nerve damage and vision loss due to glaucoma, but a lot of neurotrophic factors must be studied before the most effective treatments can be developed for everyone with glaucoma. We will not stop funding experts and propelling research until a cure is found.

Glaucoma Research Foundation depends on your donation to support innovative research and patient education. Follow this link to learn about the many ways you can join our cause.

1 "Neuroprotection in Glaucoma," April 2016, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4926571/

2 "Drug Cocktail Could Restore Vision in Optic Nerve Injury," January 2016, http://vector.childrenshospital.org/2016/01/drug-cocktail-could-restore-vision-in-optic-nerve-injury/

3 "Restoration of Visual Function by Enhancing Conduction in Regenerated Axons," January 2016, https://www.ncbi.nlm.nih.gov/pubmed/26771493

Last reviewed on October 29, 2017

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