Millions of photoreceptor cells in the eye are responsible for converting light into signals that can be transmitted to the brain and processed. When these cells malfunction or are damaged, vision loss often results.
Laboratory tests over the past two decades have shown that when photoreceptors are transplanted into the retina (i.e., the light-sensitive layer of tissue at the back of the eye) vision loss can be reversed. Valerie Wallace, a senior scientist at the Donald K. Johnson Eye Institute, and her research team have observed a phenomenon that helps explain how these cells restore vision.
“Transplanted cells rarely integrate into the retina, yet they are somehow still able to rescue vision,” says Arturo Ortin-Martinez, a scientific associate in Wallace’s lab and the lead author of the study. “Understanding this process will enable us to improve the success of transplants.”
The researchers found that donor cells form microscopic, tunnel-like bridges—called nanotubes—with the host photoreceptors. Materials that are essential to photoreceptor function can move between the cells via these nanotubes.
Using microscopy techniques that can track proteins and other components of cells, the team observed the nanotubes forming and extending as protrusions from the donor cells towards the recipient cells. They then saw materials moving between the cells.