1 - Early stage retinal cells are taken from a newborn mouse
2 - They are transplanted into the retina of a mouse which has lost its sight
3 - The cells implant and connect with existing cells in the eye, restoring some sight to the mouse.
Posted on 11/08/2006 5:49:43 PM PST by Dog Gone
British scientists have managed to make blind mice see, a breakthrough that could open the way to treating millions of people who lose their sight.
A team successfully transplanted retinal cells into mice that were blind as a result of a genetic defect, the effects of which are very similar to the human disease retinitis pigmentosa.
The treated mice regained some vision, and the team responsible showed that the transplanted cells integrated into the retina and formed new photoreceptors, the cells that are sensitive to light. The loss of photoreceptors underlies many causes of blindness in human beings, from macular degeneration to diabetes.
The team, from University College London (UCL), Moorfields Eye Hospital, London, and the University of Michigan, achieved its results by using cells that had already begun the transformation from stem cells into dedicated retinal cells. They believe that this is the key to their success.
Previous attempts using stem cells — they have the capacity to develop into all the specialised cells of the body — had failed. There was little evidence in these experiments that stem cells can integrate into the retina and become photoreceptors, perhaps because they lack the signals needed to bring this change about. Robin Ali, of the Institute of Ophthalmology at UCL, said: “We worked on the theory that cells at a later stage of development might have a higher probability of success upon transplantation.”
The cells used by the team have been programmed to be, but have yet to become, mature photoreceptors. This means that once transplanted, they are primed and ready to integrate with the retina.
A second encouraging feature of the research, reported in Nature, is that the retina accepted the new cells.
Jane Sowden, co-leader of the research, said: “Remarkably, we found that the mature retina, previously believed to have no capacity for repair, is in fact able to support the development of new functional photoreceptors.”
It seems possible that the eye already possesses a source of such cells. On the margin of the retina there are cells with stem cell-like properties — that is, cells capable of self-renewal.
“These could be harvested through minor surgery and grown in the lab to become photoreceptor precursors before being reimplanted on the retina,” Professor Ali said.
Robert MacLaren, an eye surgeon at Moorfields Eye Hospital, and a member of the team, said: “We are now confident that this (photoreceptor transplantation) is the avenue to pursue to uncover ways of restoring vision to thousands who have lost their sight.”
The evidence that the blind mice could see is indirect, but the team carried out two tests that convinced them. They took measurements of the electrical signals triggered in the next layer of cells when the eyes of the treated mice were exposed to light, and found that there were such signals, unlike untreated mice. They also showed that the pupils of the eyes of the treated mice responded to light, shrinking as the light became brighter. This showed that their eyes were sensitive to light, which was not the case with untreated mice.
An ophthalmologist unconnected with the research, Andrew Dick, of the University of Bristol, said that it was “a stunning piece of research that may in the distant future lead to transplants in humans to relieve blindness”.
If there aren't any blind mice anymore, will they have to change the nursery rhyme?
These weren't stem cells. But they believe that they can reproduce equivalent cells in humans from adult or embryonic stem cells.
"If there aren't any blind mice anymore, will they have to change the nursery rhyme?"
Maybe they only used one and ther are 2 left!
I'm not sure what you call them if they're not stem cells and they're not something else.
The author conveniently left out the TYPE of stem-cells used. It has been proven that embryonic stem cells do nothing positive (that they know of) and that they cause TUMORS to grow. The implication at the end was simply a means of misleading the reader who is ignorant of those facts.
But the article says that existing stem cells around the eye seem to be promising.
Yeah, nowhere does it say "embyonic" until the throwaway bit at the bottom about lung cancer, but it's pretty obvious to most readers.
Do you not think that if this story was about embryonic stem cells it wouldn't have been front and center?
"Adult stem cells = 72
Embryonic stem cell = 0"
TRUE, BUT:
Thomas Edison -
Light bulb material failures = 999
then
Light bulb materisl success = 1
So, let us persevere with embryos and succeed.
sounds like a recipe for success, successful businesses follow that example dont they?
This doesn't destroy humans beings, it destroys potential human beings, just like nature (40% of all embryos never make it - in nature).
Why continue with embryonic stem cells?
Because the adult stem cells are already differentiated, and can only become individualized, and not systemic.
EG heart stem cells can only become hearts, etc.
And embryonic stem cells may be able to cure systemic diseases, like Michael Fox's parkinsons desease or my type 2 diabetes, or my wife's cancer (too late now though for her).
Heh. Very good!
Ah Yes but will stem cells grow back their tails????
Is there a benefit in using adult stem cells then? If there's such a high failure rate of embryos, why not use stem cells from adults? It seems there's a proven viability there.
1 - Early stage retinal cells are taken from a newborn mouse
2 - They are transplanted into the retina of a mouse which has lost its sight
3 - The cells implant and connect with existing cells in the eye, restoring some sight to the mouse.
Honestly if Edison had found the prefect filament first would he have wasted his time and money proving the other 999 were no good?
--The author conveniently left out the TYPE of stem-cells used.--
He identified the type of cells. You have assumed incorrectly that they were stem cells.
--the article is very evasive about what brand of cells are used.--
No, they were very specific .... "retinal cells"
see 32
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