Part 2: Stem Cells to be Safe, Too

Part 2: Stem Cells to be Safe, Too

Last week we celebrated the announcement of improved vision in the first two patients receiving stem cells transplantation.  Truly exciting and encouraging news, but also due to the fact that the methods used seem safe, too.

New medical discoveries, treatments, drugs, devices, etc. must all be shown (proven) to be both safe and effective for the patients.   Last week, the “results” of these two patients hint that RPE stem cell transplantation may be effective, that is, stems cells have the hope of improving vision.

Stem cells, and their implementation, pose several risks and potential technical challenges.

In summary, human stem cells were cultivated to become RPE (retinal pigment epithelium) cells.  These are the very cells defective in retinal diseases such as macular degeneration and Stargardt’s Disease.

RPE cells (retinal pigment epithelium) usually “live” in a layer just beneath the retina.  The stem cell derived RPE cells were then injected underneath the retina.

Non-functioning diseased cells are replaced by healthy cells derived from stem cells.

Unrestricted Growth of Cells

Unrestricted growth of cells, by definition, is a tumor.  Fortunately, there were no signs of abnormal proliferation either in the eye or elsewhere in the body.  This has been reported to be a problem in animal studies.  Why might this be a problem?

Stem cells have two attributes  that make them so attractive.  Not only do they have the potential to transform into almost any type of cell in the body, but they have the potential to multiply indefinitely.

These attributes might allow scientists to create the right type of cells and make them in large quantities.

Are Stem Cells Immune?

Another potential problem may be whether or not these “foreign” cells are immunologically tolerated by their new hosts.  In theory, the new cells could be attacked by the immune system of each host (i.e. the patient receiving the cells).  In anticipation of possible “rejection,” each patient was given low dose medicines to suppress, temporarily, any immune response.

The retina may be immunologically protected by the blood-brain-barrier.

Other factors may also contribute to a shorter than expected life span of the cells, but at 4 months the cells seem to be thriving and functioning.

Technical Challenges to Transplanting the Cells

The actual process of implantation could cause a retinal detachment.  The cells were actually injected underneath the retina.  In doing so a small hole was created, allowing the potiential for a retinal detachment to occur.

One of the largest challenges, from a retinal standpoint, is how to safely transplant the cells without causing further harm to the eye.

Neither patient sustained any complications from the procedure.

What Does This Mean?  The news of stem cells improving vision for these patients is very promising.  The news of doing so in a safe manner is a “home run.”

Just as important as the science is the technology…and the ability to implement the science.







  • Joseph Exline
    Posted at 23:37h, 08 February Reply

    I t would appear as we all learned something recently. We appreciate the objective and informed report.I wish you and your readers all the best. Have a good day and hopefully if deserving,this therapy will be available to all of those in need.

    • Randall V. Wong, M.D.
      Posted at 12:08h, 14 February Reply

      Thanks for your input!

      We’ll see, but I agree, this looks very prommising.


  • Dick Marquis
    Posted at 20:58h, 09 February Reply

    This procedure is limited to Dry Macular Degeneration only, right? Not possible in the case of the wet variety?

    • Randall V. Wong, M.D.
      Posted at 12:12h, 14 February Reply

      Dear Mr. Marquis,

      In cases where there is extensive damage/loss of RPE, this would indeed be very helpful.


  • Saad
    Posted at 16:36h, 11 February Reply

    Hi Dr. Wong,
    I wonder if stem cell can treat Retinal Detachments?
    On the same note, is there any lens type recommended for those whom had Retinal Detachments surgery?

    Appreciate your feedback.

    • Randall V. Wong, M.D.
      Posted at 12:21h, 14 February Reply

      Dear Saad,

      Perhaps stem cells can improve lost vision AFTER retinal detachment surgery. That remains to be answered. There is no particular implant that comes to my mind needed following retinal detachment surgery.


  • santhosh kumar
    Posted at 15:49h, 13 November Reply

    hi dr,
    i lost vision in my right eye due to retianal detachment in an accident,. will it helpful to my eye,.. and one of the doctor in india doing stem cell therapy,.. im going to consult that doctor,.. plz give me the suggestion,…

    • Randall V. Wong, M.D.
      Posted at 07:16h, 17 November Reply


      Not sure there is any successful stem cell approach for retinal detachment.


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