Scientists at the National Institutes of Health (NIH) have created a new surgical technique that allows doctors to implant multiple tissue grafts into the retina. This breakthrough, tested in animals, could lead to better treatments for dry age-related macular degeneration (AMD), a major cause of vision loss in older adults. The findings were published today in JCI Insight.
In AMD, the light-sensitive tissue at the back of the eye begins to break down. Researchers are developing ways to repair the damage using tissue grafts made from stem cells that come from the patient’s own body.
Until now, surgeons could only insert one graft into the retina. This limited how much of the retina could be treated and made it harder to test different therapies side by side in research studies. Comparing grafts directly is important to understand how well they integrate with the retina and the nearby blood vessels, especially a small network called the choriocapillaris that feeds the retina.
To solve this, NIH researchers designed a special surgical clamp that keeps eye pressure stable during the process of placing two tissue patches one after the other. The design also helps reduce harm to the surrounding eye tissue.
In animal tests, scientists used the new method to insert two different grafts into the same damaged area of the retina. One graft contained retinal pigment epithelial (RPE) cells grown on a biodegradable scaffold. These cells play a key role in supporting the retina’s light-sensitive cells, known as photoreceptors. The other graft contained only the scaffold, acting as a control.
After the surgery, researchers used artificial intelligence to study images of the retina. They found that areas with the RPE grafts showed more surviving photoreceptors. In contrast, photoreceptors near the scaffold-only grafts were more likely to die.
Importantly, the team also confirmed that the RPE grafts helped restore the choriocapillaris. This is the first time scientists have shown this type of regeneration, which is vital for supplying the retina with oxygen and nutrients.
These findings support ongoing efforts in an NIH-led clinical trial that is testing RPE grafts made from a patient’s own cells to treat dry AMD in humans.
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