NIH scientists pioneer new retinal transplant technique for dry age-related macular degeneration

NIH scientists pioneer new retinal transplant technique for dry age-related macular degeneration

Scientists at the National Institutes of Health (NIH) have developed a new surgical technique for implanting multiple tissue transports into the retina of the eye. The findings in animals may help advance treatment options for age-related macular degeneration (AMD), a leading cause of vision loss in older Americans. A report on the technology published today inJCI Insight.

In diseases like AMD, the light-sensitive retina tissue degenerates in the background. Scientists are testing therapies to repair damaged retinas using lab-grown tissue transplants of patient-derived stem cells. Previously, surgeons could only place one graft in the retina, limiting the area that can be treated in patients and the ability to perform side-by-side comparisons in animal models. Such comparisons are crucial to confirm that the tissue grafts integrate with the retina and the underlying blood supply from a network of tiny blood vessels known as the choriocapillaris.

For the technique, investigators designed a new surgical clamp that would immediately maintain eye pressure during the insertion of two tissue patches while minimizing damage to surrounding tissue.

In animal models, the scientists used their newly designed surgical technique to compare two different grafts placed one after the other in the same experimentally induced AMD-like lesion. A graft consisted of retinal pigment epithelial (RPE) cells grown on a biodegradable scaffold. RPE cells support and nourish the light-sensitive photoreceptors of the retina. In AMD, vision loss occurs alongside loss of RPE cells and photoreceptors. In the laboratory, RPE cells are grown from human blood cells after they have been converted into stem cells. The second graft consisted of only the biodegradable scaffold to serve as a control.

After the surgery, scientists used artificial intelligence to analyze retinal images and compare the effects of each transplant. They observed that the RPE grafts promoted photoreceptor survival, while photoreceptors near scaffold grafts died at a much higher rate. In addition, they were able to confirm for the first time that the RPE transplant also regenerated the choriocapillaris, which supplies the retina with oxygen and nutrients.

The results expand capabilities demonstrated in an ongoing, NIH-led, first-in-human clinical trial of derived RPE grafts for dry AMD.

The work was supported by the National Eye Institute Intramural Research Program.

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