Perspectives on new stem cells for vision loss paper

F2 Kashani et al. Stem cells for vision loss
stem cells for vision loss
Kashani, et al. Science Translational Medicine, 2018, Figure 2

Do stem cells for vision loss offer real hope?

I believe so, but it’s a long road and must be done right.

A new paper in this area generated some buzz on top of an earlier recent pub (mentioned in this post) just a week or so ago about the potential of stem cells for vision loss.

The new paper is entitled, “A bioengineered retinal pigment epithelial monolayer for advanced, dry age-related macular degeneration” and is Kashani, et al.

They generated special eye cells called retinal pigmented epithelial cells or RPE from embryonic stem cells and a bio-device with the RPEs was implanted in 4 patients. RPE don’t directly function in vision (sensing light), but can help to keep other cells in the eye happier and healthier, including importantly photoreceptors.

I’m cautiously upbeat about this work for a number of reasons, but mainly because of the safety profiles and not because of any possible hints at efficacy reported.
For years, there was concern that using human pluripotent stem cells as the basis for therapies including for vision loss, even if the stem cells themselves were only used to generate differentiated eye cells for subsequent transplant and were not themselves directly part of the treatment, might be too dangerous as they have the potential to form benign but destructive tumors called teratomas. This new work along with other studies including using IPS cells point to a reassuring overall inherent safety profile so far. While there have been some adverse events, they appear to relate specifically to the procedures involved rather than the cells themselves and importantly there haven’t been tumors so far.
The major caveat with this and other similar work is that they are small, open-label studies without control groups, meaning that they do not have the power to determine if any observed potential small signs of efficacy such as hints at improved vision or halting of loss of vision are real and due to the cell therapy. So the jury is still out on stem cells for vision loss.
The clinical work led by Masayo Takahashi is still of great interest as well and is focused on using IPS cell-derived RPEs too. They have not observed tumors, but there have been challenges there that have slowed things down somewhat including the report in January of a membrane forming after introduction of stem cell product.
Another pluripotent stem cell-based effort at stem cells for macular degeneration ongoing for many years is the work led by Robert Lanza of Astellas, work that began in the company ACT and then renamed Ocata. It’s been very quiet on this front since Astellas acquired this research program. When I last communicated with Bob in May 2017, he indicated the work was very much ongoing still, but I’m hoping somehow we’ll all get another update soon.
Why has this all been so hard and time-consuming?
Beyond the challenges mentioned earlier with potential risks associated with pluripotent stem cell-based approaches that necessitate extra caution and take a lot of time, more broadly it is very challenging to translate any kind of stem cell therapy from the bench to the bedside in a responsible way that doesn’t put too much risk or financial burden on patients, and has a solid chance of efficacy. This is demanding, extremely complex research thatI’d say is harder than rocket science. Also, we have to be very careful to avoid hype.
You can see just how badly rushing unproven stem cells for eye problems at the far other end of the spectrum where unproven, for-profit stem cell clinics have sold offerings to patients, reportedly leading to retinal detachment and loss of vision (here and here).
In the long run, I think that stem cells for vision will succeed and they are going to be the basis for proven, safe therapies, but we need to do it right in terms of the research.


  1. This is amazing, and it is so great to read a piece about the issues with AMD research and especially this specific paper. I keep recommending this site to people precisely because Paul Knoepfler is such a cautious researcher. There aren’t going to be any over the top promises of miracle cures here. That having been said– I think that there needs to be much more fast tracking and accelerated approval of these treatments. I just don’t think that we have the luxury of waiting for something like a double-blind study (which really isn’t possible anyway. It would be much more irresponsible to subject half the patients to a sham surgery.) The reason is very pragmatic. People are incredibly desperate, and they’ll do anything for even the slightest chance of a cure. If they can’t get a treatment that has had any decent research done on it at all, then they’ll go to an illegal stem cell clinic, spend everything they have, and end up with a disastrous result. The entire situation is like battlefield triage. Professionals are going to have to make some hard decisions. Is it better to insist on perfect protocol and perfect research conditions while people are driven to desperate tactics that have little to no chance of helping them, or to make compromises and at least give people a fighting chance?

    I don’t pretend to know what the answers are. But desperate people do desperate things, and I think that factor is really being underestimated. We can already see that people will spend money they don’t have and sign away their rights to object if things go wrong with stem cell clinics, even as they probably know deep down that their chances are slim at best. If medicine has any hope of a cure to offer that is real– and I think that whatever else we do or don’t know about the AMD studies, this much can be said– then maybe the lesser of two evils is to have it available, even when all of the ideal studies have not been done.

  2. Paul, I’m still trying to find out why the Lanza/Astellas program has apparently still not up and running. According to the latest info I have, their Phase II Clinical Trial (NCT03178149) for dry AMD, which was supposed to begin recruiting patients last month, is still not yet recruiting. I have several feelers out seeking information.


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