S
AY goodbye to your reading glasses.
Researchers at Japan’s RIKEN Centre
for Developmental Biology have
restored vision in mice with end-stage
retinal degeneration – the leading cause
of irreversible vision loss and blindness
in elderly humans – by transplanting
retinal tissue grown using stem cells.
Patients with conditions such as age-related
macular degeneration and retinitis pigmentosa
lose vision as a result of damage to the outer
layer of light-sensitive photoreceptor cells in
the eye. There is currently no cure for this,
only therapies aimed at stopping the
progression of vision loss.
The team genetically reprogrammed skin
cells taken from adult mice to an embryonic,
stem cell-like state, and then converted these
into retinal tissue. When transplanted into mice
with end-stage retinal degeneration, the stem
cell-derived retinal tissue developed to form
photoreceptors – specialised neurons within
the retina that send vision signals to the brain.
“No one has really shown transplanted stem
cell-derived retinal cells responding to light
in a straightforward approach, as presented
in this study, and we collected data to support
that the signal is transmitted to host cells that
send signals to the brain,” said researcher
Michiko Mandai.
When the treated mice were placed in a box
consisting of two chambers, with one rigged up MANDAI ET AL/STEM CELL REPORTS 2017, JOHN BRETT/OXFORD EYE HOSPITAL, GETTYto deliver electric shocks through the floor,
they were able to see a warning light and avoid
the shocks by moving from one chamber to
the other. “We showed that visual function
could be restored to some degree by
transplantation of the stem cell-derived retina,”
said Mandai. “This means that those who
have lost light perception may be able to see
a spot or a broader field of light again.”
Next up, the researchers will test tissue
derived from human stem cells in mice,
with the ultimate goal of moving on to clinical
trials in humans.“It is still a developing-stage
therapy, and one cannot expect to restore
practical vision at the moment,” said
Takahashi. “We will start from the stage
of seeing a light or large figure, but hope to
restore more substantial vision in the future.”Adding stem cell-derived
tissue to damaged mouse
retinae restored some visionEXPERT COMMENTPROF ROBERT MACLAREN
Professor of ophthalmology, University of Oxford, the UK
“This study is exciting because it shows that
a complicated part of the central nervous system,
such as the retina, could potentially be regenerated
from something as simple as a skin cell. Furthermore,
the engineered retinal tissue appears to be able to make
connections to the brain after transplantation.
Clinical treatments are still a long way off,
but, for patients with retinal degeneration,
this provides some hope for the future.”“VISUAL
FUNCTION
COULD BE
RESTORED TO
SOME DEGREE”
| MEDICINEDISCOVERIES28 April 2017