As I wind down the week at the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO), I’d like to introduce an intriguing therapeutic approach to retinal degeneration that would be a home run if perfected. It’s called retinal regeneration, and it happens to be right in line with the National Eye Institute’s life-changing audacious goal, announced on Monday: “to regenerate the neurons and neural connections in the eye and visual system.”
One reason that retinal degenerations are so devastating is that, once photoreceptors are lost, they don’t grow back. As you may know, the Foundation is funding a number of promising projects to replace lost retinal cells with those derived from a number of sources, including a patient’s own skin or blood.
But a potentially more elegant approach to overcoming retinal degenerative diseases would be to stimulate the patient’s retina to regenerate its own photoreceptors. In some animals — namely, fish and amphibians — the retina can regenerate. Unfortunately, such is not the case in people — at least not yet.
But there’s hope for retinal regeneration for humans, thanks to Foundation-funded researcher Dr. Thomas Reh, who has reported progress on this treatment approach at a couple of ARVO sessions. Dr. Reh is investigating how to derive new photoreceptors from retinal cells called Muller glia. In the developed retina, Muller glia provide architectural support and a number of protective and waste-disposal functions.
But Dr. Reh has shown that Muller glia can be reprogrammed in a dish to become neurons — cells that are closely related to photoreceptors. Much more work remains, but if he can derive photoreceptors from Muller glia in a mammal such as a mouse, it would be a major step toward making retinal regeneration possible in humans.
A key benefit of a regenerative treatment is that researchers don’t have to worry about getting transplanted cells to functionally integrate with the patient’s exiting retina. That’s a big hurdle at the moment. Regeneration would also eliminate the concern of potential immune reactions that might come from newly introduced photoreceptors.
At this stage of the game, retinal regeneration is definitely an audacious goal; unlike stem cell therapies now in clinical trials, regeneration is several years away from becoming a reality. But we have to keep thinking big. Just 15 years ago, we had no idea that we could even grow new retinal tissue from stem cells. But we have come a long way since then.
Finally, please keep in mind that the ARVO meeting is just a snapshot of where the research is today. We are making new advancements all the time, and our progress is accelerating like never before. Is it fast enough? Absolutely not. But we have the audacity to keep urgently driving the research until everyone can see.
Pictured, above: Dr. Thomas Reh
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Steve is highly respected for his expertise and tireless commitment to finding treatments and cures for vision-robbing retinal diseases.
As the Foundation's senior science writer, Ben writes science and research articles for the Foundation’s website, newsletters and Eye on the Cure blog.
As the Foundation's senior writer, Rich writes and edits content for all of the Foundation’s print and online publications, including its blog, Eye on the Cure. 
Might this one day work for someone with LCA patients carrying a rare gene? My grandson age 4 is blind and we were told the defective gene has not been identified yet.
Hi Linda,
As I mentioned in response to an earlier comment, retinal regeneration may benefit people with a variety of diseases including Leber congenital amaurosis. It will depend on which cells are affected by the disease and which cells we are able to regenerate. We generally known which cells are affected, but we are just beginning to learn which cells we may be able to regenerate.
I think it is important for you to have your grandson’s DNA re-tested to try and find the disease-causing genetic mutation – that will help determine which treatments are most likely to benefit him.
While stem cell, glial regeneration and gene therapies for retinitis pigmentosa hold great promise for the future, these therapies are many years away from clinical application. There is one treatment that could be available relatively soon, it seems to me. Ciliary neurotrophic factor (Neurotech’s ECT implant) has demonstrated safety and efficacy (retinal receptor layer thickening and receptor preservation in a pilot study). Do you have any information about the development of this promising therapy? It has long had orphan drug and fast track status yet the last studies date to 2009. What is the reason for this delay?
Thanks for your comment Kenneth,
The key to getting a treatment approved by the FDA (or other regulatory agency) is demonstrating that it can save or restore vision. Neurotech has shown that the ECT may have a positive effect on retinal health, but the company needs to show that the positive effect translates to vision improvement or preservation. That is the challenge at the moment.
There is an ongoing AOSLO imaging study of the ECT taking place at UCSF. The ultimate goal is to get the FDA to validate new imaging endpoints for this type of therapy, so that regulatory approval can be obtained. Here is an article describing that work:
https://www.blindness.org/index.php?option=com_content&view=article&id=3292:fda-grant-expands-foundation-funded-study-of-powerful-retinal-imaging-technology-&catid=65:retinitis-pigmentosa&Itemid=121
Neurotech is also conducting clinical trials of the ECT for the treatment of wet AMD.