Research targets RGC repair, replacement, regeneration

Fort Lauderdale, FL-Different strategies have been investigated in retinal ganglion cell (RGC) repair, replacement, and regeneration as therapies for glaucoma; some are promising, others less so. Keith R.G. Martin, MD, MRCP, FRCOphth, described what is happening in this field and some of the new treatments at the annual meeting of the Association for Research in Vision and Ophthalmology.

Regarding the repair of RGCs, an essential component is minimizing the extent of damage and the spread of injury through neuroprotection and stimulation of endogenous cells, Dr. Martin said.

"Animals with replacement abilities often have retinal 'progenitor cells' in the CMZ that persist throughout life and that can add new rings of neurons to the retina as it grows," Dr. Martin explained. "These animals may also have mature cells elsewhere in the retina that can transdifferentiate in response to injury.

If the restricted types of cells produced by the CMZ in post-natal chicks are due to limited growth factors in the microenvironment, exogenous factors might be applied to neural stem cells in the mature central nervous system to stimulate proliferation, direct cellular fate, and regenerate particular types of neuron, he emphasized.

Glaucoma as target "Glaucoma is a neurodegenerative disease defined clinically by characteristic optic nerve damage with loss of RGCs and visual field," Dr. Martin said.

"We can slow the death of RGCs in glaucoma by slowing progression through treatment to lower the eye pressure, but can we replace cells that have already died?" he asked.

Of interest to researchers is whether ganglion cells lost as the result of glaucoma can be replaced by stem cells/neural progenitor cells.