The Use Of Stem Cells To Cure Blindness

In a groundbreaking study (Stem Cell Therapy Makes Cloudy Corneas Clear, Science Daily), scientists may have discovered a minimally invasive way to utilize a person’s own stem cells to treat and repair damaged corneas. The formation of scar tissue that can result from illness or trauma to the eye can cause the cornea to become opaque and thus lose its transparency, leading to blindness.

Since corneal scarring is permanent, the current therapy to treat the damaged tissue has been to replace it. Each year about 40,000 transplants are performed in the U.S. They are usually successful in treating vision problems, but they are an extremely delicate procedure and are largely unavailable to people in developing countries.

Transplants are also, for the most part, not permanent and come with the inherent problems of finding a suitable match as well as the possibility of tissue rejection. Furthermore, the pool of potential donors, which is already limited, is being affected by the rise in popularity of Lasik surgery, which renders the cornea unfit for transplantation.

The use of a person’s own cells would get around many of these problems, especially in lieu of the fact that the stem cells in question are actually present in the mature eye, residing in the fibrous tissue of the corneal stroma. These cells apparently produce the key compounds required for the production of the stromal tissue, one of which was identified as the protein, lumican. These stem cells, however, are largely inactive, and don’t step in to repair damage when it happens. The body seems to opt for the quickest, most efficient path of repairing the damage (by way of scar tissue) rather than actually replacing it.

Researchers at the University of Pittsburgh School of Medicine, however, were able to take these stem cells out of the eye and propagate, or clone, them in the laboratory. They were then injected into the eyes of laboratory mice who were unable to produce lumican and were consequently suffering from degenerative corneal blindness.

Afterward, the corneas actually cleared up and normal vision was restored. Interestingly, the human cells were able to colonize the mouse eyes, without the usual tissue rejection problems that can complicate transplantation Experiments have been undertaken that looked how the procedure would fair in human tissue using eyes from tissue banks. These organs were no longer usable for transplantation, and the results were promising.

Even still, human testing is years away, but it is a very promising first step, and because the stem cells can be generated from the recipient themselves, i.e., the recipient and donor are one-the-same, there are no problems of tissue rejection or time lost searching for a suitable donor.

In the end, the implications for stem cell therapy are huge, not just for the eyes but for the entire body, and the findings represent yet another example of the potential promise that stem cell therapy holds for the future.

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