A groundbreaking study published in Stem Cell Reports demonstrates that human stem cell-derived retinal sheets can successfully repair macular holes in a non-human primate model. Researchers transplanted sheets derived from human embryonic stem cells into the eyes of Japanese macaques with macular holes. Advanced imaging confirmed that the transplanted cells closed the defects anatomically. Crucially, the stem cell-derived cells matured into functional photoreceptor cells (rods and cones), which are essential for high-resolution vision. Functional recovery was also observed: treated primates showed improved eye fixation and spatial response, with benefits persisting months after treatment. The team addressed a major hurdle in stem cell therapies — immune rejection — by using localized steroid injections, which effectively mitigated mild rejection responses at three and six months. While the results are promising, the researchers note that synaptic connections between the transplanted cells and the host retinal neurons have not yet been fully confirmed, which is a critical step for full visual restoration.
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