NIH researchers report animal model validation for stem cell-based approach to advanced dry AMD
A group of NIH researchers say they have laid the groundwork needed to tackle the root cause of an advanced form of age-related macular degeneration by reprogramming adult blood cells into retinal cells in rat and pig models. And now they plan to move that into an historic breakthrough effort in humans.
The scientists from the NIH’s National Eye Institute set out to prevent blindness in geographic atrophy, or advanced dry AMD. Retinal pigment epithelial cells nurture photoreceptors; when they die (usually in the early stage of geographic atrophy) the photoreceptors lose protection and eventually die as well, ultimately resulting in blindness. With the results and protocols detailed in a Science Translational Medicine paper today, they are hoping to set the stage for a first-in-human study.
The cells used in the autologous treatment goes through three stages: They begin as a patient’s blood cells, get converted into induced pluripotent stem cells (iPSCs), and are finally programmed to become retinal pigment epithelial (RPE) cells and thinly layered on a scaffold. RPE cells nurture photoreceptors; their death marks the early stage of geographic atrophy, also known as advanced dry AMD.
By patching in iPSC-derived RPE cells to replace the dying ones, researchers theorized they could keep the photoreceptors — light-sensing cells — functioning properly, thus maintaining vision.
As far as they could tell, it worked.
“Ten weeks after the human iPSC-derived RPE patches were implanted in the animals’ retinas, imaging studies confirmed that the lab-made cells had integrated within the animal retina,” a release reads. The lab-made cells also grew mature enough to keep the photoreceptors alive and healthy.
The researchers also checked to make sure the RPE cells they grew had no genetic mutations linked to cancer growth, a “key concern with any stem cell therapy.”
The leading cause of blindness among the elderly affecting more than 5 million worldwide, geographic atrophy has once inspired megablockbuster dreams at Roche for its eye drug lampalizumab — which was quietly scraped after failing both Phase IIIs. Kentucky-based biotech Apellis has more encouraging data with its complement C3 inhibitor. With an IND pending, stem cell-based therapy will soon become another candidate to claim the first approved treatment for the disease.