First Successful Skin-to-Eye Stem Cell Transplant in Humans

Special cells taken from the skin and turned into retinal cells show promise for treating age-related macular degeneration (AMD), the leading cause of vision loss among the elderly, a new study shows.

AMD has long been considered an inevitable disorder of aging and is the primary cause of blindness in industrialized countries, affecting more than 2 million people in the United States alone (and that number is expected to double by 2050). A form called wet-type AMD causes the abnormal growth of new blood vessels in the eye that can leak blood or protein, damaging the retina. AMD is currently incurable, but a breakthrough study using induced pluripotent stem cells (iPS), conducted by the Riken Center for Developmental Biology in Kobe, Japan, may change the way we treat AMD and other diseases of the eye. The iPS cells are adult cells (as opposed to embryonic stem cells) that can be genetically altered to go back into a near-embryonic state and from there be programmed to develop into any type of cell found in the body.

In 2014, Riken researchers, in conjunction with the Institute for Biomedical Research and Innovation (IBRI), developed a sheet of retinal cells from iPS cells and successfully implanted the sheet into the back of the eye of a 70-year-old woman with AMD. These iPS cells were engineered from her own arm skin cells.

The new study, led by ophthalmologist Masayo Takahashi of Riken Center, has followed the patient’s progress for about a year and a half since the transplant took place. The goal of this pilot clinical study was to confirm the safety of iPS cell therapy and see if it could prevent further degeneration of the patient’s vision.

“We assess if the transplanted cells are rejected and if the cells show any malignant characteristics,” Yasuo Kurimoto tells mental_floss. The director of the department of ophthalmology at the Kobe City Medical Center and the IBRI, Kurimoto, performed the surgery.

Today—one year and seven months after the operation—the patient is doing well. So far the researchers haven’t seen any sign of rejection or problems with the transplanted cells, says Kurimoto, who presented the results at the Association for Research in Vision and Ophthalmology (ARVO)’s 2016 annual meeting in Baltimore in early May.

The surgery itself only took about two hours to perform and caused only minimal bleeding and post-operative swelling of the eye, according to Kurimoto. Most promising, he says, is that while the patient’s visual acuity was in a state of decline before the iPS cell implantation, after the surgery “her visual acuity is preserved without additional treatment for AMD."

The treatment holds promise for other eye diseases such as Stargardt’s disease or other ailments in which retinal pigment epithelium cells start to degrade.

The researchers hope that in future trials they may be able to use iPS cells to repair or even encourage regrowth of damaged cells. Their next line of research will look into producing and transplanting photoreceptor cells in experimental animals to test the safety of the procedure. “In future we would like to carry out iPS-derived photoreceptor cells transplantation in patients with photoreceptor degeneration such as retinitis pigmentosa,” Kurimoto says.

They also aim to begin treatment sooner. While the subject of the current study was in an advanced stage of AMD, the researchers’ next objective is to treat patients in earlier stages of AMD so “their vision will be preserved better,” Kurimoto says.