Part 1: Introduction to Stem Cells and Retinal Disease

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Part 1: Introduction to Stem Cells and Retinal Disease

Part I of a series regarding stem cell transplantation. It may be the cure for macular degeneration and other diseases.

This is the first of a small series regarding stem cells and their potential benefits to retinal diseases; principally macular degeneration and retinitis pigmentosa.

As diabetic retinopathy is primarily a disease of blood vessels, i.e.poor blood flow, loss of blood flow, leaking vessels, etc., macular degeneration is actually a disease of one of the layers of the retina.  Specifically, the layer affected is called the Retinal Pigment Epithelium (RPE).  It is a layer of cells that have numerous functions and responsibilities, one of which is keeping the photoreceptor healthy and happy.  Remember photoreceptors are also known as rods and cones.

The retina is a laminated tissue. It lines the inside of the eye in the same way that wallpaper lines the inside of a room.  Just underneath the retina is a layer of cells, the Retinal Pigment Epithelium (RPE).  The RPE layer is uniformly found underneath the entire retina, even the macula.  For us to “see,”  the retina must be attached and all the layers of the retina be healthy.  This is not so in macular degeneration.  While the retina is attached, the RPE layer becomes sick and dysfunctional; it degenerates.  It is the RPE layer that is diseased in macular degeneration.

Cross Section of Eye with Inset

In areas of the macula where the RPE has become dysfunctional, the vision is impaired.  Symptoms include blurry vision and distortion.  The actual cause of the degeneration of the RPE is not known; it may be due to poor blood supply from a vascular layer deep to the RPE (the choriocapillaris, aka choroid),  it may be purely bad genetic programming or it may be due to environmental factors (e.g. sun, smoking, etc.).

How to Replace Damaged Cells? Retinal Pigment Epithelium cells do not reproduce or regenerate.  Once the RPE is damaged, the eye can not make more.  The focus of research has been, how to replace damaged RPE cells?

Several approaches to replace Retinal Epithelium Cells are under experimentation.  Attempts at direct transplantation have had some success.  Stem cell transplantation, in theory, seems very promising.

More tomorrow.

“Randy”

Randall V. Wong, M.D.
www.TotalRetina.com
Ophthalmologist, Retina Specialist

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Comments
  • Indrajit Roy May 19, 2010 at 12:01 pm

    Please help me to get the information about the treatment of Retinal Deattachment along with the details of the hospital if any has done the treatment with Stem Cell. What was the recovery rate?

    • Randall V. Wong, M.D. May 21, 2010 at 6:32 am

      I am sorry, but I am not privy to any studies experimenting with stem cells for retinal detachment.

      Randy

  • Karthik November 3, 2010 at 5:09 am

    Hi, i was born with congenital cataract which was followed by a detached retina in my left eye at the age of 16. Even after many surgeries, i lost the vision in that eye. I am 25 now. I just want to know if at all it is possible to replace my detached retina to get some vision back in my lifetime?To tell you frankly,i am not bothered about the vision, but the appearance more…since i just cant seem to get a good fitting prosthetic made,it makes me depressed all the time…Thanks very much in advance for the reply…eagerly waiting for it…

    • Randall V. Wong, M.D. November 3, 2010 at 7:39 am

      Karthik,

      It is not possible to to replace your detached retina. We are not there yet, and it doesn’t seem likely in the near future.

      With regard to the prosthesis, keep moving forward. In my patients that have lost the eye (yes, it happens) due to diabetic retinopathy or longstanding retinal detachments, there are wonderful oculoplastic surgeons available that can help you get the prosthetic “fit” that you need.

      I am sorry I don’t have better news for you.

      Thanks for sharing.

      Randy

  • Karthik November 5, 2010 at 9:14 am

    Thanks very much for the reply sir! Yes i am aware that there are no existing treatments available…because i know that moorfields eye hospital london has been conducting stem cell research and Gordon Brown, the british ex-pm(who also lost vision due to RD) is still one eyed..but just wanted to know if it is physically feasible at all from a medical point of view…because if it is, then i think we can expect some headway in another 10-15 years… which is still some hope for me!! Thanks again!

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