Claims on a Stem Cell Treatment for Blindness

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New Stem Cell Treatment Can Restore Sight to the Blind

Stem cell therapy for retinal disease is under way, and several clinical trials are currently recruiting. These trials use human embryonic, fetal and umbilical cord tissue-derived stem cells and bone marrow-derived stem cells to treat visual disorders such as age-related macular degeneration, Stargardt's disease, and retinitis pigmentosa.[1]


In a study that claimed the success of this innovation, the researchers initially started out with blind mice. The stem cells injected into the rear of the eye were able to replace the damaged photoreceptors which are vital in vision.[2] Although the scientists attributed their success to their good choice of stem cells, the study was just a case study that cannot be used as evidence of the discovery of a new treatment modality. In fact, they admitted that there were still a number of challenges and risks that came with that treatment.

A different article that was published in the New England Journal of Medicine also showed that there are challenges in the use of stem cells to restore sight to the blind. According to the article, doctors reported that three women suffered severe, permanent eye damage after stem cells were injected into their eyes, in an unproven treatment at a loosely regulated clinic in Florida. One of the patients, aged 72, completely lost her sight while the others, aged 78 and 88, lost much of their eyesight after paying $5000 each to receive stem-cell injections with the hope of successful recovery from macular degeneration.[3]

Scientists have long hoped that stem cells might have the power to treat diseases, but it's always been clear that they could be dangerous too, especially if they're not used carefully. Some of the more interesting concerns are related to which methods are going to be used to generate stem cell-derived RPE (retinal pigment epithelium), what is going to be the immune reaction against such cells, and what approaches are going to be developed in order to deliver this cells into the eye of the patient. These are complicated issues that should be explored along with broader issues of efficacy and safety.[4]  

The U.S Food and Drug Administration (FDA) is concerned that the hope that patients have for cures not yet available may leave them vulnerable to unscrupulous providers of stem cell treatments that are illegal and potentially harmful. FDA cautions consumers to make sure that any stem cell treatment they are considering has been approved by FDA, or is being studied under a clinical investigation that has been submitted to and allowed to proceed by FDA. Presently, FDA has approved only one stem cell product, Hemacord, a cord blood-derived product manufactured by the New York Blood Center and used for specified indications in patients with disorders affecting the body’s blood-forming system.[5]

At this very moment, several early phase human clinical trials are in progress around the world and the results will no doubt be exciting, but continued research and collaboration are needed among funding sources, academic labs, and industrial partners to ensure success, since there is no established treatment at present.[6]

In order to ensure the success of a procedure of this magnitude, there are the following several developments that need to be researched and tested:

  • Development of novel, non-invasive diagnostic tests to assay RPE and retinal function at the molecular and cellular level.
  • Development of novel transplantation tools and surgical methods for optimal delivery of RPE to the subretinal space.
  • Expansion and advancement of stem-cell science for the purpose of understanding host immune response in the sub-retinal space.
  • Developing clinical grade methods to genetically modify stem cell–derived RPE.[7]

Other studies consider that, even though technology is bringing the prospect of this procedure from dream to reality, there is one major impediment to overcome: transplanted RPE cells showed limited adhesion and survival in human eyes, and aged Bruch’s membrane did not likely support adhesion, survival, differentiation, and function of grafted RPE cells.[8][9] Because of this, we need to develop a specific method that allows these cells to over-express integrins or integrin activators in the RPE cells to facilitate adhesion and survival after the procedure.[10] This evidence points out that even though we are closer than before, we have not yet reached a level of genetic engineering to allow this to happen.



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