Human retinal stem-like cells with potential to repair vision loss discovered

Wenzhou Medical University and collaborating institutions have identified a population of human neural retinal stem-like cells able to regenerate retinal tissue and support visual recovery.

Vision loss caused by retinal degeneration affects millions worldwide. Conditions such as retinitis pigmentosa and age-related macular degeneration involve the irreversible loss of light-sensitive neural cells in the retina. While current treatments may slow progression, they do not replace damaged tissue.

For decades, scientists have explored whether stem cells could be used to regenerate the retina, but the existence of true retinal stem cells in humans has remained uncertain. In fish and amphibians, the outer edge of the retina houses stem cells that regenerate tissue continuously. Whether a comparable system exists in the human eye has been debated for more than two decades.

In the study, "Identification and characterization of human retinal stem cells capable of retinal regeneration," published in Science Translational Medicine, researchers used single-cell and spatial transcriptomic methods to investigate the presence and identity of retinal stem-like cells in humans.

Researchers examined human fetal retinal tissue from four donors at 21 weeks of gestation, using spatial transcriptomics and single-nucleus sequencing to identify and localize cell types in the retina.

Researchers analyzed gene expression and chromatin accessibility to detect populations with stem cell–like properties. Additional samples from donors between 16 and 22 weeks of gestation were used to confirm the location of these cells in the peripheral retina.

A distinct population of neural retinal stem-like cells was identified in the peripheral retina of human fetal tissue. Located in the ciliary marginal zone, these cells showed molecular features consistent with self-renewal and the ability to differentiate into all major retinal cell types. Similar cells appeared in the same anatomical region of retinal organoids, with overlapping gene expression profiles.

Following injury in organoids, stem-like cells migrated into the damaged area and produced new retinal cells. Gene activity during the repair process matched patterns observed during natural fetal development.

In a mouse model of inherited retinal degeneration, transplanted cells remained viable for up to 24 weeks. Donor cells integrated into the host retina, developed into mature retinal types, and formed connections with neighboring cells. Treated animals exhibited improved retinal structure and stronger visual responses compared to controls.

Human retinal stem-like cells demonstrated the capacity to regenerate tissue and restore visual function across both fetal tissue and retinal organoid models. In both injury models and transplant experiments, the cells demonstrated the ability to restore retinal structure and contribute to visual function.

Post-transplantation, the cells remained viable for at least 24 weeks, differentiated into photoreceptors, ganglion cells, and bipolar cells, and formed functional synapses with host tissue. Treated mice demonstrated improved retinal morphology and performance in visual function assays across multiple time points. No intraocular tumors were observed following transplantation.

Compared to previously studied retinal progenitor cells, this population showed broader differentiation capacity and longer-term viability. Transplanted cells contributed to retinal structure and restored visual function in mice, without adverse effects.

Results suggest that retinal organoids may serve as a source of human stem-like cells for future research and therapeutic development. Further studies will be needed to assess safety, immune compatibility, and effectiveness in models that more closely resemble human disease.

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