Researchers at the University of Nebraska Medical Center on Tuesday announced a significant step in adult stem cell research that could take science closer to cures for glaucoma and age-related macular degeneration.
A team led by Iqbal Ahmad, professor of ophthalmology and visual sciences, used adult stem cells from the cornea, the clear window at the front of the eye, and reprogrammed them to act like cells in a developing baby’s retina.
The retina, located at the back of the eye, transforms light into neural signals that can be interpreted by the brain, an essential part of vision.
Ahmad said the team’s work built off that of Drs. John B. Gurdon and Shinya Yamanaka, who won this year’s Nobel Prize in science after they genetically altered adult stem cells to mimic embryonic stem cells.
Before the pair's discovery, scientists believed embryonic cells, which have far greater potential to develop into different types of cells, could come only from embryos.
In that early breakthrough, researchers directly manipulated gene expression inside cells to cause them to reset themselves to a more primitive state.
The real advance of Ahmad’s team came in causing adult stem cells to change by placing them in a chemical environment similar to what might be encountered inside the eye of a developing fetus.
The team next took the reprogrammed cells and transferred them into a mice model of glaucoma, where they survived and integrated just like actual retinal ganglion cells -- the interface between cells that react to light and nerve cells.
The experiments took place in a dish, but the reprogrammed cells did hook up as desired, Ahmad said.
“They have the potential to restore the circuitry.”
In a coming experiments, he said, researchers will try to discover whether the new cells truly integrate in ways that could restore sight.
The group’s approach might be adapted to resolve other problems that cause blindness, he said, such as age-related macular degeneration.
In that case, the adult stem cells could be reprogrammed by a different chemical environment to resemble the eye’s photoreceptors, cells that react to light. Those cells are very similar in makeup to retinal ganglion cells.
Such modified cells also can be studied to see what genes are responsible for sight degeneration and what genes fight vision loss. This could lead to drugs that block the degenerative genes or bolster genes that fight vision loss, Ahmad said.
“We’ve shown that changing the environment around these adult stem cells can change the cells themselves,” Ahmad said. “We now seek more efficient ways to create these transformative environments to cultivate these powerful cells that may offer hope to so many.”