A new source of stem cells may cure vision loss

Researchers have discovered a new source of stem cells at the back of the eye, and the hope is that these cells may one day be able to repair the damage that age-related macular degeneration (AMD) does to the sight of those over 60-years-old.

In an interview with CBC, Sally Temple, a developmental neuroscientist at the Neural Stem Cell Institute, said, “We’re just thrilled to have found these cells because we know that age-related macular degeneration affects so many people, something like 10 million people in North America.”

Her team, whose research is described in the January edition of Cell Stem Cell, found the central nervous system stem cells behind the retina, in a single layer called the retinal pigment epithelium (RPE). The retina is responsible for converting light into electrical signals that the brain translates into images.

She noted that these cells are easily accessible from living people, a breakthrough in medical science. “You can literally go in and poke a needle in the eye and get these cells from the sub-retinal space. It sounds awful, but retinal surgeons do it every day. These cells are laid down in the embryo and can remain dormant for 100 years. Yet you can pull them out and put them in culture and they begin dividing. It is kind of mind-boggling,” Temple said, adding that accessing other neutral stem cells would require major surgery deep within the brain.

Her team was able to develop a progenitor cell that is similar to a type of nervous system cell.

“The fact that we could make these cells that were part-way, that were immature, indicates to us that if we keep on manipulating them, going forward in the future, we should be able to find ways to create other types of central nervous system cells. And a really important cell type that we’d love to see if we can make would be the retinal cells, the neural retinal cells like the photoreceptors that are in the eye. So if we could help make new photoreceptors as well as the RPE — which we’ve already shown we can make — then we would be making two really valuable cell types for age-related macular degeneration.”

Researchers are also interested in making new photoreceptors. “A really important cell type that we’d love to see if we can make would be the retinal cells, the neural retinal cells like the photoreceptors that are in the eye. So if we could help make new photoreceptors as well as the RPE — which we’ve already shown we can make — then we would be making two really valuable cell types for age-related macular degeneration,” said Temple.

When it comes to potentially curing AMD, the ultimate goal for her team is to regenerate eye tissue destroyed by the disease so eyesight can be restored.

So far, lab tests on animals indicate the cells are stable and do not seem to cause tumors, one of the dangers characteristic in some forms of stem cells. According to Temple, more animal testing is needed to determine if they can actually restore lost vision.

If all goes as planned, the first trial of the safety of AMD treatment using these stem cells on humans could begin in five years.

ON THE WEB

Read the abstract for the study, Adult Human RPE Can Be Activated into a Multipotent Stem Cell that Produces Mesenchymal Derivatives.

Sources: Cell Stem Cell, CBC

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