Stem cells close to cornea may help treat Macular Degeneration or Retinitis Pigmentosa

Scientists at the Southampton General Hospital and the University of Southampton have found a pool of stem cells around the corneal limbus that can be induced to become retinal cells. Such cells can then potentially be transplanted into the eye of the patient of macular degeneration or retinitis pigmentosa to stop the disease or even cure it.  


The corneal limbus is a readily accessible region at the front of the eye, separating the cornea and sclera. This region has become well known to corneal surgeons for the presence of corneal limbal stem cells. Limbal stem cell transplant is an accepted modality of treatment for some corneal pathologies. 

Neural colonies (neurospheres) can be generated from adult corneal limbus in a culture medium. The same group of researchers had earlier concluded in a study published in the British Journal of Ophthalmology that corneal limbal stromal progenitor cells are a potential and convenient autologous cell source to generate functional neurons.

In this recent study, published in the journal PLoS One, the researchers investigated whether mouse and human limbal neurosphere cells (LNS) could differentiate towards a retinal lineage both in vivo and in vitro following exposure to a developing retinal microenvironment. The scientists have been able to demonstrate that LNS can be generated from adult mice and aged humans (including in the eyes of a 97-year-old, opening up the possibility that the treatment could work for the elderly).

Generation of neurospheres from adult mouse and human limbal cells (Credit: PLoS ONE)

Following culture with developing mouse retinal cells, retinal progenitor cell markers (signifying that tests proved that such cells were in early stages of retinal cell development), mature retinal/neuronal markers and sensory cilia were detected in the majority of mouse LNS experiments. After transplantation into the sub-retinal space of neonatal mice, mouse LNS cells expressed photoreceptor specific markers (proving that they were similar to photoreceptors), but no incorporation into host retinal tissue was seen. Human LNS cells also expressed retinal progenitor markers at the transcription level but mature retinal markers were not observed in vitro or in vivo.

This data highlights that mouse corneal limbal stromal progenitor cells can transdifferentiate towards a retinal lineage (indicating they can form retinal cells). Complete differentiation is likely to require more comprehensive regulation; however, the accessibility and plasticity of LNS makes them an attractive cell resource for future study and ultimately therapeutic application.

Additional resources:  1