British scientists have discovered non-dividing retinal cells implanted into adult mouse retina can generate new photoreceptors.
The University College London researchers say their finding suggests a possible way to regenerate photoreceptors lost from many forms of blindness.
Previously, stem cells transplanted into the adult retina have not integrated correctly and it was thought the retinal environment inhibits regeneration.
Robin Ali and colleagues at UCL's Institute of Ophthalmology extracted immature retinal cells from newborn mice at a time when many rod photoreceptors are normally being generated, and transplanted them into adult mouse retinas.
The scientists found the cells differentiated into rods, formed synaptic connections and, when transplanted into certain mouse models of inherited retinal degeneration, improved the animals' response to light.
Surprisingly, they found that this was possible only using rod precursor cells during a specific time window of development, when they have stopped dividing rather than proliferating stem cells.
The results, say the researchers, suggest precursor cells grown from human adult or embryonic stem cells might also serve to restore sight, and challenge the assumption that stem cells offer the best prospect for tissue repair.
The study appears in the journal Nature.
Copyright 2006 by United Press International
Related stories:
Scientists successfully awaken sleeping stem cells
Scientists at Schepens Eye Research Institute have discovered what chemical in the eye triggers the dormant capacity of certain non-neuronal cells to transform into progenitor cells, a stem-like cell that can generate new retinal cells. The discovery, published in the March issue of
Investigative Ophthalmology and Visual Science (
IOVS), offers new hope to victims of diseases that harm the retina, such as macular degeneration and retinitis pigmentosa.
Zebrafish enables cell regeneration studies to help understand, treat human disease
One aquarium fish’s uncanny ability to regenerate essentially any cell type has given scientists a way to mimic cell loss that occurs in diseases such as Parkinson’s and diabetes then watch how the fish make more of them.
Cannibalistic signals help mammalian embryos develop normally
A cannibalistic process called autophagy spurs dying embryonic stem cells to send "eat me" and "come get me" signals to have their corpses purged, a last gasp that paves the way for normal mammalian development, UT Southwestern Medical Center researchers have found.
Fish eyes could hold clue to repairing damaged retinas in humans
A special type of cell found in the eye has been found to be very important in regenerating the retina in zebrafish and restoring vision even after extensive damage. Now, a UK team of scientists believe they may be able to use these cells – known as Müller glial cells – to regenerate damaged retina in humans, according to a study published this month in the journal
Stem Cells.
Scientists: Stem cells can make blind see
British researchers hope to make stem-cell treatment of blindness caused by macular degeneration routine within a decade.
Scientists identify key to integrating transplanted nerve cells into injured tissue
Scientists at the Schepens Eye Research Institute, an affiliate of Harvard Medical School, have identified a key mechanism for successfully transplanting tissue into the adult central nervous system. The study found that a molecule known as MMP-2 (which is induced by stem cells) has the ability to break down barriers on the outer surface of a damaged retina and allow healthy donor cells to integrate and wire themselves into remaining recipient tissue.
Stem cell therapy shows promise for rescuing deteriorating vision
For the millions of Americans whose vision is slowly ebbing due to degenerative diseases of the eye, the lowly neural progenitor cell may be riding to the rescue.
First Look at the 'Birth' of a Retina Cell
Scientists at the University of Michigan Kellogg Eye Center have gained new insight into the way an embryonic retina cell develops and then commits itself to a specific role. They have observed a small window of opportunity during which a cell has been designated to play a particular role, but has not yet begun to function as such.