26.05.2025.
Scientists have created a new way to place two retinal grafts in one eye, making it easier to compare different treatments for dry age-related macular degeneration (AMD).
In animal tests, grafts with special eye cells called RPE cells helped protect light-sensing cells and supported the growth of small blood vessels needed for healthy vision. This could help improve future treatments using lab-grown cells.
Key Facts:
- Dual grafting innovation: A new technique allows simultaneous implantation of two grafts for better comparative analysis.
- Photoreceptor preservation: Grafts containing RPE cells protected light-sensing neurons better than controls.
- Vessel regeneration: RPE grafts uniquely regenerate the choriocapillaris, crucial for retinal support.
- Age-related macular degeneration (AMD) is a common condition that affects the middle part of your vision. It usually first affects people in their 50s.
- It does not cause total blindness, but it can make things like reading and recognising faces difficult.
- Without treatment, your vision may get worse. This can happen gradually over several years before it can then get worse quickly over a few weeks or months.
- The exact cause is unknown. It’s been linked to things such as ageing, smoking, high blood pressure, being overweight and having a family history of AMD.
In animal models, the RPE grafts significantly preserved light-sensing photoreceptors and regenerated the choriocapillaris, the blood vessel layer essential for retinal health. These results enhance ongoing efforts to translate lab-grown stem cell therapies into clinical treatments for vision loss.
In diseases such as AMD, the light-sensitive retina tissue at the back of the eye degenerates. Scientists are testing therapies for restoring damaged retinas with grafts of tissue grown in the lab from patient-derived stem cells.
Until now, surgeons have only been able to place one graft in the retina, limiting the area that can be treated in patients, as well as the ability to conduct side-by-side comparisons in animal models.
Such comparisons are crucial for confirming that the tissue grafts are integrating 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 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.
