Restoring vision in AMD may be a possibility with stem cell transplantation.
Cadaver eyes are now considered another source of RPE stem cells. “These are cells that amazingly can be obtained from 9-year-old patients and can clonally proliferate in a dish and be transplanted later,” Dr. Rao said.
An interesting point for consideration is that some of the most commonly used cells lines are not homogenous as was once thought and can acquire mutations in the dish, e.g., H1 and H9 lines contain inactivating TP53 mutations, Dr. Rao related.
Some of these cells have been transplanted into eyes, but no reports of tumor growth have yet emerged.
“We should keep in mind that these embryonic stem cells and their derivatives may be carrying cancer-related mutations. Also pluripotent female cells have higher epigenetic instability due to nonrandom X inactivation patterns used in the earliest trials,” he commented.
Transplantation of stem cells is an emerging technology, and to now, investigators have learned the following. Hyperpigmentation does not necessarily represent engraftment and can also indicate released pigment from dead cells. The procedures are associated with development of retinal detachment, epiretinal membrane, PVR, and intraoperative and postoperative subretinal hemorrhage.
It is unclear is there is sustained visual improvement or whether there is visual improvement at all in some of the trials. Evidence indicates that at higher doses there is hyperpigmentation associated with loss of visual function by microperimetry, Dr. Rao concluded.
Rajesh Rao, MD
Dr. Rao has no financial interest in any aspect of this report.