First skin-to-eye stem cell transplant shows promise, researchers say
Stem cells, which have been likened to "utility" players in sports because of their remarkable capacity to transform and fill in for other kinds of cells in the body, are showing their versatility as a potential treatment for wet age-related macular degeneration (AMD).
The first-ever transplant of human skin cells was performed on a 70-year-old Japanese female patient in September 2014. Just weeks ago on May 3, researchers involved in that transplant provided an update on their pilot study at the annual meeting of The Association for Research in Vision and Ophthalmology in Seattle, Washington.
More than a year later, they report, the patient is doing fine.
Her immune system has not rejected the implanted stem cells, achieving the primary purpose of the pilot study: seeing whether the transplant could be done safely. In the clinical trial, skin cells from the patient were used to generate induced pluripotent stem cells (iPSCs). Those cells were then used to create a retinal pigment epithelium (RPE) sheet that was then implanted in the woman's eye.
Her vision acuity remained the same clinically but she reported greater satisfaction with her sight.
"The patient underwent iPSC/RPE transplantation (and) is doing well after the surgery so far," Yasuo Kiromoto, M.D., Ph.D., one of the study's researchers, writes in an email. "We will keep monitoring the patient to prove the long-term safety of the iPSC-derived RPE therapy and to evaluate the long-term efficacy of the transplantation."
Dr. Kiromoto adds, "Our success of this trial will promote the development of iPSC-based therapy in the whole field of medicine."
Dr. Kurimoto, who performed the two-hour transplant, is affiliated with Kobe City Medical Center General Hospital in Japan. The research was a joint project of RIKEN, the IBRI (Institute for Biomedical Research and Innovation) Hospital, and the Kobe City Medical Center General Hospital.
A leading cause of severe vision loss in adults over age 50, AMD affects 1.8 million Americans with millions more at risk for the condition.
If detected early enough, wet AMD can be treated so that the growth of leaky blood vessels is slowed and the loss of vision minimized. But there is no cure. Japanese researchers noted in their study that, after the implant, the anti-vascular endothelial growth factor drug was no longer needed and "visual acuity was preserved up to now."
Stem cell potential
Stem cells as a treatment option for AMD is an exciting development, says Steven Ferrucci, O.D., chief of optometry at Sepulveda VA Medical Center and professor at Southern California College of Optometry at Marshall B. Ketchum University. Dr. Ferrucci has written and lectured extensively on AMD.
"Stem cells hold great promise in treating a myriad of eye disorders, such as AMD," Dr. Ferrucci says. "Early research made great strides in the surgical procedure that allows stem cells to be implanted into the eye.
"But newer studies are looking at using an individual's own corrected stem cells, derived from their skin, and implanting these into the eye, rather than using donor fetal stem cells," he adds. "The theory is that by using one's own cells, the chance of rejection is significantly reduced. This study and others have demonstrated great improvement in the surgical technique that allows such transplantation."
It's worth noting that the clinical trial involved only one patient.
Researchers had hoped to undertake transplants in six people. However, they stopped recruiting subjects after new guidelines were issued in Japan on regenerative medicine. Researchers are looking at jumpstarting new trials.
"This is promising," Dr. Ferrucci says. "But it still may be several years until stem cells are viable for our patients on a widespread basis, and even longer until we know the visual implications. Nevertheless, studies such as this are an important first step in the search for successful treatment with stem cells."
The AOA follows all research closely, including potential treatments for AMD; however, more research is needed regarding stem cells' influence on visual health.
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