NIH researchers have developed a new surgical method to implant multiple retinal tissue grafts, potentially expanding treatment options for dry age-related macular degeneration (AMD). The approach, demonstrated in animal models, allows for broader retinal coverage and enables side-by-side comparisons of graft integration. Current techniques permit only a single graft, limiting therapeutic potential and evaluation. The new method supports assessment of graft interaction with both the retina and the underlying choriocapillaris. Findings were published in JCI Insight.
For the technique, investigators designed a new surgical clamp that maintains eye pressure during the insertion of two tissue patches in immediate succession while minimizing damage to the surrounding tissue.
In animal models, the scientists used their newly designed surgical technique to compare two different grafts placed sequentially in the same experimentally induced AMD-like lesion. One graft consisted of retinal pigment epithelial (RPE) cells grown on a biodegradable scaffold. RPE cells support and nourish the retina’s light-sensing photoreceptors. In AMD, vision loss occurs alongside the loss of RPE cells and photoreceptors. In the lab, RPE cells are grown from human blood cells after they’ve been converted into stem cells. The second graft consisted of just the biodegradable scaffold to serve as a control.
Post surgery, scientists used artificial intelligence to analyze retinal images and compare the effects of each graft. They observed that the RPE grafts promoted the survival of photoreceptors, while photoreceptors near scaffold-only grafts died at a much higher rate. Additionally, they were able to confirm for the first time that the RPE graft also regenerated the choriocapillaris, which supplies the retina with oxygen and nutrients.
The findings expand on the capability demonstrated in an ongoing, NIH-led first-in-human clinical trial of patient-derived RPE grafts for the dry form of AMD.
The work was supported by the National Eye Institute Intramural Research Program.
Read the full news release from NIH National Eye Institute.
Source: National Eye Institute