This is an image taken through a fluorescence microscope of neural progenitor cells, or NPCs. Progenitor cells are similar to stem cells in that they can develop into other types of cells.

These particular progenitor cells can mature into three different types of cells:

• Neurons - nerve cells
• Astrocytes - star-shaped cells that surround and support the neurons in the brain and spinal cord
• Oligodendrocytes - cells that insulate and protect the long fibers that extend from neurons

This image was taken one week into their maturation to confirm these cells are multipotent, meaning they can grow into all these different cell types.

Our research shows that transplanting these progenitor cells into the retina prevents vision loss in our laboratory animal models. Otherwise, they would become blind from progressive retinal disease, similar to human diseases like age-related macular degeneration and retinitis pigmentosa, a disease in which the retina is damaged. We're figuring out how these cells work in order to maximize their therapeutic benefit.

We're hoping to understand how these cells could be used to help prevent blindness that can occur because of disease. At one time, the conventional wisdom was that stem cells replace tissues lost to disease—but that doesn't explain the vision rescue that we and other researchers have seen with these transplants.

It seems the cell grafts improve the function of the existing retinal cells and prevent them from dying, protecting them long-term. By identifying the precise molecular signals the NPCs use to exert their effects, we hope to determine which diseases will respond best to them. Our observations that the cells function through multiple mechanisms suggests that vision rescue from multiple diseases may be possible for patients who currently have ineffective treatments or no treatment options at all.