Transplanted retinal ganglion cells marked with a fluorescent tag. Image credit: Thomas Johnson and Johns Hopkins Medicine
In experiments in mouse tissues and human cells, Johns Hopkins Medicine researchers say they have found that removing a membrane that lines the back of the eye may improve the success rate for regrowing nerve cells damaged by blinding diseases. The findings are specifically aimed at discovering new ways to reverse vision loss caused by glaucoma and other diseases that affect the optic nerve, the information highway from the eye to the brain.
In the current study, Johnson and his team grew mouse retinas in a laboratory dish and tracked what happens when they added human retinal ganglion cells, derived from human embryonic stem cells, to the surface of the mouse retinas. They found that most of the transplanted human cells were unable to integrate into the retinal tissue, which contains several layers of cells.
After using an enzyme to loosen the connective fibers of the internal limiting membrane, the researchers removed the membrane and applied the transplanted human cells to the retinas. They found that most of the transplanted retinal ganglion cells grew in a more normal pattern, integrating themselves more fully. The transplanted cells also showed signs of establishing new nerve connections to the rest of the retinal structure when compared with retinas that had intact membranes.