27 September 2010
ByAppeared in BioNews 577
Researchers have successfully transplanted retinal cone cells into blind mice, making progress towards a stem cell treatment for a form of blindness that causes degeneration of the eye's retina. The research team, from the University College London Institute of Child Health, isolated immature photoreceptors - light-sensitive cells - from the developing retina.
They transplanted these cells into the eyes of adult mice with Leber's congenital amaurosis, a form of degenerative blindness. The transplanted cells integrated into the retina and became mature 'cone' photoreceptors, the cells required for colour vision.
Dr Jane Sowden, who led the study, said: 'The newly developed cones look as good as new. This is an important step forward as cone photoreceptors are essential for reading vision and for colour vision, and loss of this type of cell has the biggest impact on sight'.
'It may be possible to translate this success into treatments for humans. Recent research has shown that embryonic stem cells capable of self-renewal could provide an equivalent source of human cells that... could be grown in the lab before being transplanted in the retina'.
Retinal degenerative disease is the leading cause of untreatable blindness in the developed world, and is caused by the death of photoreceptor cells. The two main types of photoreceptor present in the retina are rod cells, involved in night vision, and cone cells, essential for daylight and colour vision. When cone cells die, severe loss of vision occurs.
The researchers previously showed that photoreceptor precursor cells transplanted into a degenerating eye could integrate into the retina and mature into rod photoreceptors, partially restoring vision in adult blind mice.
In the new study, published in the journal Human Molecular Genetics, they showed precursor cells taken from a different stage of eye development could mature into cone photoreceptors when transplanted into the eyes of blind mice. Further studies are needed to see if the transplanted cells can help to restore vision, and to determine whether the technique would work in humans.