In a research first, a section of light-sensing tissue, closely resembling
the human retina, has been grown in the laboratory from human stem cells.
Maria Canto-Soler, an assistant professor of
ophthalmology at John Hopkins University in the USA, and lead author of the
study, said: 'We have basically
created a miniature human retina in a dish that not only has the architectural
organisation of the retina but also has the ability to sense light'.
Using iPSCs, the researchers first generated precursor
retinal cells by growing them in a medium containing specific growth factor chemicals. The researchers were surprised to see that the cells assembled into a complex
structure, in steps similar to those observed in the eye during fetal
The tissue not only structurally resembled the human
retina, but it also contained all major retinal cell types arranged in their
Dr Canto-Soler said: 'The stem cells could build up the
retinal structure almost autonomously. Somehow the cells knew what to do and we
just needed to give them time to do it'.
The scientists were also interested to see whether
their model was able to give rise to functional photoreceptors, the light-sensing cells of the retina. Photoreceptor damage is a common cause of
They found that their artificial retina contained
cells that not only resembled photoreceptors structurally, but were also able
to respond to light.
Dr Canto-Soler commented that this finding 'advances
opportunities for vision-saving research and may ultimately lead to
technologies that restore vision in people with retinal diseases'.
She also highlighted, however, that light-sensing only provides a small
part of the vision-making process. 'Is our lab
retina capable of producing a visual signal that the brain can interpret into
an image? Probably not, but this is a good start'.
retina was tested at a stage equivalent to 28 days of fetal development and the
scientists will now try to develop their model further.
Gamm of the University of Wisconsin, a co-author
of the study, told The Scientist: 'Knowing the
mechanism in greater detail will allow us to improve the retinal
differentiation process, making it more safe, reproducible, and user-friendly
for both disease modelling and drug testing and for clinical transplantation into
Talking to The Scientist, Dr Canto-Soler,
however, said: 'there is still a long way to go before we can directly apply this to patients'.
The research was published in Nature Communications.