Research into macular degeneration is aimed at:

stopping the disease from developing
treating it so that the disease process stops
reversing damage that has been done
curing it

I’ve shared many examples of each of these areas. You’ll find links at the end to 4 of my articles about research for wet AMD, for dry AMD, for gene therapy research, and for a cure.

In this article, we’ll look at what’s being done in clinical trials to reversing damage and to restore vision that has been lost.

Reversing Damage That Has Been Done

What about those who have an advanced form of macular degeneration and have suffered vision loss? This can occur in any form of macular degeneration including AMD, Stargardt’s Disease, and Myopic Macular Degeneration. The stem cell research applies to all of these.

Vision loss occurs when the photoreceptors die. These cells transmit signals to the brain which is where we get our sight. They convert ‘light to sight.’ They die because the cells that keep them alive called RPEs (Retinal Pigment Epithelium) falter and die. These RPE cells are critical to the retina’s ability to dispose of waste and to make sure the photoreceptors are nourished. We know that retinal cells don’t regenerate, so researchers have been asking the questions:

Can we keep the RPE cells healthy? Can we replace RPE cells that have died? If we do that, can we restore vision that is lost?

There is research into replacing photoreceptors, but it’s more difficult to do. It is currently being explored in the lab and with animals which is called pre-clinical research.

Restoring RPE Cells – Restoring Sight?

The answer to those questions about RPE cells have been found in the area of stem cell research. What are stem cells? They are specialized cells in our body that can make other types of cells. No other cells can do that. The stem cells used in research come from different sources. You can learn more about them in National Institute of Health’s Stem Cell Basics and A Closer Look at Stem Cells.

Here’s a very simplistic explanation as to why stem cells are of interest in retinal repair:

If they can make other types of cells, can they make RPE cells? The answer is yes! These new RPEs are called stem-cell-derived RPEs, and they’re created by the ‘magic’ of science (it’s complicated!) in the lab.
If we could take those stem-cell-induced RPEs and get them into the retina, could they replace failing or dead RPEs and keep the photoreceptors alive?

That’s exactly what researchers are working on.

Warning

The topic of using stem cells is one that has been discussed in MANY areas of healthcare. For retinal repair, there is NO proven safe and effective use of stem cells as a treatment for macular degeneration outside clinical trials which follow procedures that are rigorous and based on the scientific method. The first step is to establish the safety of the proposed treatment – that’s Phase 1. Only if the treatment is proven to be safe do the clinical trials progress to find the right dosage needed to be effective and to monitor any side effects. FDA approval comes at the end of a series of phases. You can learn more about clinical trials and why they are important by reading Treatments and Cures: Too Good to Be True? You can also find out what the FDA does and does not do related to macular degeneration.

Beware Unproven So-Called Treatments

Some people and clinics sell these unproven, not-FDA-approved stem cell treatments for macular degeneration. These costly procedures have blinded people & have not been effective for others. For more information about that, you can read FDA Warns About Stem Cell Therapies – Some patients may be vulnerable to stem cell treatments that are illegal and potentially harmful. The FDA has been working to shut down the sellers – that’s what they are – of these possibly dangerous procedures.

Unreliable Resource

The NIH National Library of Medicine has an online resource available called clinicaltrials.gov. It’s where researchers can list their studies which can be accessed by patients, their family members, health care professionals, and the public. Unfortunately, the site has no oversight, no vetting of the entries to make sure they are legitimate studies. Just because you find something that sounds interesting to you or someone you love, it doesn’t mean it is something to seriously pursue. You need to do much more research. I recommend the article Nine Things to Know About Stem Cell Treatments.

Stem Cell Research for Retinal Repair

The FDA approved their use for retinal repair in 2010. You can read about the early research in the 2018 article Stem Cell Treatment in Retinal Diseases: Recent Developments. Also, you can watch a great 2018 video Retinal repair: Bringing stem cells into focus.

The study of using stem cells is called regenerative medicine.

The Basics

Since retinal repair research started in 2010, the studies have varied primarily in two aspects:

1. The source of the stem cells. The options used so far are embryonic stem cells and induced pluripotent stem cells which are adult cells that are reprogrammed to look and act like embryonic stem cells. You can read about these in What Are Stem Cells and How Do They Work. The more recent research has moved to using the induced pluripotent stem cells for several reasons: use of embryonic stem cells has raised ethical issues, they are hard for researchers to get, have a higher risk of rejection, and they can migrate to other places with a possibility of creating tumor cells.
2. The method of transplanting the stem-cell derived RPEs. The purpose is to get these new cells in the area of the RPEs so they can be integrated with them. Initially, the cells were put into a suspension (a fluid) and injected into the retina. Unfortunately, those stem cells didn’t stay where they were placed. With the help of engineering experts, more recent research has put these cells on a monolayer (single layer) of a material to keep them together so that when they are implanted in the retina, they will stay in that area. The designs vary. Some other terms for this approach are patch, scaffold, layer, implant, or sheet.

Summary of the Concept

The basic way stem cell research is conducted is that ‘new’ RPE cells are created in the lab from stem cells and injected into the retina. Hopefully, these stem-cell-derived RPEs should then integrate with the person’s own RPE cells so that they can do what RPE cells do: nourish and clean up after photoreceptors. Sounds simple, yes? It isn’t. There are issues regarding rejection of these new cells and the safety of using immunosuppressive drugs, their possible migration to other places in the body where they may create tumors, safety of the method that delivers the stem-cell-derived RPEs, and more. That’s why the clinical trial process is so important!

The History

As I wrote above, the FDA approved the use of stem cells for retinal repair in research in 2010. Phase 1 clinical trials started that year. The purpose of phase 1 clinical trials is to make sure the treatments are safe. Since stem cell research for retinal repair was so new, researchers were very careful. These early studies used embryonic stem cells with their possible complications. One early trial was stopped out of concern for the participants.

Since then, many clinical trials have been done.

When doing your own research on this topic, make sure to check the dates of the resources since much has changed since 2010.

Two early Phase 1 studies were started in 2010 by Advanced Cell Technology (then called Ocata which became Ocata Therapeutics; it’s Astrellas currently). Professor Steven Schwartz, MD, and colleagues reported that 4 months after the first patients had the procedure they found no safety issues of tumor growth or rejection from using embryonic stem cells and no loss of vision. In 2015, they reported that of the 18 patients treated, more than half had improvements in visual acuity. They found evidence that the new RPE cells were integrated in the retina. They also reported that although the treatment was safe, which meets the objective of a phase 1 clinical trial, more follow-up was needed.

I could give you a LONG list of articles about the clinical trials that came after this one. A lot of progress was made, a lot was learned. I want to fast-forward to where we are today with this promising research.