Wednesday, January 25, 2012

Stem cell treatment restores visual impairment

Shortly after scientists have reported on a new therapy to restore vision by means of gene therapy, another research group has shown success in human patients by using a stem cell therapy. A study performed in Massachusetts, USA on two persons with a form of macula degeneration got their vision partly restored after an injection with stem cells. Though there is a fair amount of controversy around stem cell therapy, the study shows how important research on this topic is.

Because the macula is a central part of the retina in the human eye, degeneration results in impaired vision which increases over time. The macula itself is most often visible as a yellow spot, because it contains a lot of cells tasked with detecting the outside light required for proper vision. In macula degeneration, for whatever reason many cells die. Naturally, this results in decreased signal conduction to the brain, where the actual images of what we see are formed. The researchers in Massachusetts used an injection of cells to restore the loss of cells in this area, hoping that they would replace the dead cells by taking over their function.
Because it is an highly experimental procedure, only two patients with a degenerating macula, one age-related and one with an inherited form, were enrolled in the study. Both of them increased the quality of their vision after being injected with about 50,000 eye cells created from embryonic stem cells. Equally important, the stem cells did not show any of the occasional nasty side effects, such as tumour formation. Neither did the body respond to the 'foreign' cells by creating an inflammation process to get rid of them.

The researchers claim their treatment is not a cure. It is simply aimed at slowing the macula degeneration, to delay its onset. It means that prospective patients will be able to hang on to their vision for longer. Additionally, because the therapy proved to be safe, the stem cells may be used during an earlier phase in the disease, to increase their impact.

It is an example of a promising stem cell therapy. The world of science is in need for success regarding stem cells in the clinic, as their use is controversial. Despite recent success of culturing embryonic stem cells in the lab and improvement of culturing techniques, human embryos are still often used as a source for the cells. Stem cells have been hallowed as being able to repair anything, but so far have yielded little usable therapies. Most of the success was gained by using artificially made stem cells, such as in the treatment of spinal cord injuries. However, a recent study also demonstrated a usable therapy for embryonic stem cells.

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