Human stem cell transplants have successfully repaired macular holes in a monkey model, according to researchers. After the transplant, the macular holes were closed by continuously filling the area with retinal tissue.
According to researchers, human stem cell transplants have successfully repaired macular holes in a monkey model, as reported on October 3rd in the journal Stem Cell Reports. Following the transplant, the macular holes were closed by a consistent influx of retinal tissue.
“For the first time in a non-human primate model, we have confirmed that transplantation of embryonic stem cell-derived retinal organoid sheets promotes the closure of macular holes,” stated Michiko Mandai, the senior study author from the Kobe City Eye Hospital. “These findings indicate that this method could serve as a practical, safe, and efficient treatment option, particularly for challenging macular hole cases, with minimal risks of invasion.”
Macular holes are small openings in the macula, the central area of the retina in the eye. They can lead to blurred or distorted central vision, making tasks like reading, driving, or discerning fine details difficult. In the last ten years, advancements in surgical techniques have resulted in closure rates exceeding 90%, yet stubborn cases remain problematic. Managing recurring macular holes after surgery poses challenges as well. For diseases that cause retinal degeneration, cell-based therapy offers a hopeful avenue for restoring vision. Although retinal transplants have shown good anatomical success, improvements in vision are often limited, and peripheral visual field defects generally occur.
In this new research, Mandai and her team explored whether they could tackle these challenges by transplanting sheets derived from human embryonic stem cell retinal organoids. The procedure resulted in graft survival, maturation, and the generation of light-sensitive retinal cells known as photoreceptors, which include rods and cones. Further experiments showed enhancements in eye fixation and light response.
However, the researchers noted some limitations, including mild rejection of the transplant, which they managed through steroid injections. “This mild rejection could have hindered the functional integration of the transplanted tissue,” says Mandai. “Moreover, this was an isolated outcome from one eye, and the model did not perfectly replicate the characteristics of human refractory macular holes. Nevertheless, the results indicate that the surgical method is feasible for treating human macular holes.”
The authors emphasize that additional research is required to confirm the benefits of the stem cell-derived retina, particularly its protective effects on surrounding retinal cells. Moreover, more studies are necessary to understand how the composition of the graft impacts visual function. The researchers intend to investigate whether a form of synaptic communication can be established between the host tissue and the graft over an extended period.
