Image: Peter Mallen

Promising new results come from The Schepens Eye Research Institute today that demonstrate how surgeons might eventually be able to turn a blind eye back into a seeing one. The work, reported in the journal Molecular and Cellular Neuroscience, marks the first instance of transplanting stem cells, the progenitors of all cells, into diseased eyes in hopes of regenerating damaged retinas--thin sheets of cells in the back eye that collect patterns of light. In fact, many forms of blindness result from illnesses that injure the retina, including macular degeneration, glaucoma and diabetic retinopathy.

Michael Young and colleagues derived neural stem cells from the hippocampus of adult rats and then injected them into the gel-like vitrous of eyes in rats showing retinal degeneration. In one-, four- and 10-week-old animals, the donor cells not only took, but actually migrated to the right place, started assuming the characteristics of retinal cells and extended into the optic nerve, which links the eye to the brain. In older animals the neural cells were also widely accepted. Surprisingly, the transplants worked best in the most damaged eyes.

"These cells somehow sense that they are needed, and begin to differentiate into cells that could take on the job of retinal neurons," Young comments. "It is exciting that neural progenitor cells are capable of responding to injury cues in the mature central nervous system." Although Young cautions that there is still a long way to go, he adds that "We are optimistic that this technique will one day restore vision to those who have been blinded by disease or injury."