Japanese scientists have successfully completed the first skin-to-eye stem cell transplant in humans. The procedure managed to partially restore the vision of an elderly woman suffering from age-related macular degeneration (AMD).
The results of the procedure, which took place in 2014, were shared at the 2016 conference of the Association for Research in Vision and Ophthalmology in Seattle earlier this week.
Scientists took a small 4 millimeter (.15 inch) piece of the patient's skin from her arm and modified its cells, effectively reprogramming them into induced pluripotent stem cells (iPSC), Science Alert reported.
Because pluripotent stem cells have the capability to differentiate into almost any type of tissue within the body, the skin cells taken from the arm could be repurposed into retinal tissue.
From there, the cells were developed into retinal pigment epithelium (RPE) and cultured in the lab to grow into an ultra-thin sheet. This sheet was then transplanted behind the retina of the patient.
Although the procedure took place in 2014, scientists held off on reporting the results until now, as they were focused on monitoring the patient's progress and gauging how well the modified cells lasted.
Now, they have reported that the procedure was highly successful, with the transplanted cells surviving without any adverse events for over a year.
"The transplanted RPE sheet survived well without any findings [or] indication of immune rejections nor adverse unexpected proliferation for one and a half years, achieving our primary purpose of this pilot study," the team said in a statement.
The transplant resulted in slightly improved vision for the 70-year-old patient, who suffers from AMD – a progressive eye condition which affects the macula of the eye and leads to central blindness, leaving dim images or black holes at the center of vision. The disease is the leading cause of vision impairment in older people.
Although the transplant did not result in complete restoration of the patient's vision, the procedure is promising for the future use of induced pluripotent stem cells.
Project leader Masayo Takahashi, from the Riken Centre for Developmental Biology, said at the time of the treatment: “...I have renewed my resolve to continue forging ahead until this treatment becomes available to many patients.”
Stem cell treatments have been making major strides when it comes to correcting vision impairments. Earlier this year, researchers in the US and China were able to improve the vision of infants with cataracts by manipulating protein levels in stem cells.
Furthermore, a woman in the US state of Maryland had some of her vision restored after being blind for more than five years, after stem cells were extracted from her bone marrow and injected into her eyes.
Scientists also believe that induced pluripotent stem cells could treat a range of other illnesses, including Parkinson's and Alzheimer's.