Stem Cell Transplant for Blindness, Retina Disease Nears Human Assessment

Primate model studies show the procedure can be done safely and without losing eye function. Which patients may benefit first?

New study results bring clinicians one step closer to treating degenerating vision, and even blindness, with stem cell therapy.

A new assessment from an international team of investigators showed human retinal pigment epithelium (RPE) stem cell-derived RPE (hRPESCE-RPE) transplantation—previously shown to rescue vision in a rat model of retinal dystrophy—can be conducted safely in non-human primates.

The findings, led by authors including Timothy A. Blenkinsop, PhD, of the Blenkinsop Laboratory at Icahn School of Medicine at Mount Sinai, showed hRPESCE-RPE monolayers were able to recover in vivo and maintain healthy photoreceptors at 3 months. The positive outcome could indicate the stem cell monolayer transplant could be a safe and promising prospect in human patients with chronic disease such as age-related macular degeneration (AMD).

In an interview with HCPLive® regarding the new research, Blenkinsop highlighted a trio of outstanding findings in the latest advancement of animal-model assessment for RPE transplantation: safety, maintained visual recording sensitivity and eye features, and the beginning signs of transplanting cell performance.

He stressed that non-human primates carry a high visual acuity area in their eye, boding well for consideration into human application.

Though all 7 observed models survived the procedure, Blenkinsop noted some complications from the transplantation—largely due to grafting issues, and not from the transplanted cells themselves. He believes this is a limitation which can only be resolved with greater experience going forward.

“The surgical complications have most to do with ‘practice makes perfect’,” he said. “This is the very early days, so the surgeons will only be better.”

The potential of stem cell therapy use for recovering or improving vision in patients with chronic conditions or with blindness is a long-held hope—one which is becoming better resourced and evidenced in short time. Blenkinsop said his team is currently stocked with an “inexhaustible supply” of cells from the contributing New York Eye Bank for future assessment, with a need for concise “compatibility matching” among cell antigens for would-be patients.

It is currently estimated that up to 11 million people in the US suffer from a type AMD—with that total anticipated to have doubled in a quickly aging population by 2050. Though this is the group Blenkinsop and colleagues mainly highlight as would-be benefactors of hRPESCE-RPE, many more patients with debilitating ophthalmic conditions could become eligible as the science advances.

“The cells we are transplanting are associated with dozens of eye-related diseases,” Blenkinsop said. “That is the largest population, but by no means the only population.”

The study, “Surgical Transplantation of Human RPE Stem Cell-Derived RPE Monolayers into Non-Human Primates with Immunosuppression,” was published online in Stem Cell Reports.