Stem cells have captured the imagination of the world as a 'repetoire' of immature cells that may be persuaded or cajoled into restoring or rejuvenating debilitating organs. Research carried out by a team of UK scientists have helped to reiterate this belief, by restoring sight in mice which suffered from conditions that eventually would damage the eye.
This amazing work, which was published in 'Nature', could be lauded as a 'mile stone' in stem cell research. The study was funded by the Medical Research Council (MRC) and was carried out jointly by the Institute of Ophthalmology and Child Health, University College of London and the Moors Field Eye Hospital.
The retina is considered by scientists to be the best 'arena' to study cell transplant, as the initial loss of the photoreceptor cells does not affect it, leaving it more or less intact.
The cone and rod photoreceptors of the retina, which are fundamental for vision, are irreplaceable, if lost. While new therapies are evolving that will prevent the loss of these cells, the scientists are searching for a new treatment that will prove to be a panacea to damaged cells.
For this study, advanced retinal cells, which were programmed to develop into photoreceptors, were taken from newborn mice. Five-day old mice were ideal candidates, as, in them, the retina is at the stage of formation. These cells were then transplanted into the retina of the 'designer' mice, which were genetically engineered to develop conditions like Retinitis pigmentosa or Age-related Macular Degeneration (AMD).
These experiments were successful, as the photoreceptor transplants were able to connect and synchronize with the existing retinal nerve cells, which allowed the complete revival of lost vision. The pupils of these experimental mice responded to light, and activity was observed in the optical nerve, indicating that signals were being sent to the brain. It is indeed remarkable that the mature recipient retina, which was considered to lack the potential for repair, does in fact, supports the development of the transplanted immature cells.
If the technique were to be extrapolated on to humans, it would involve taking stem cells from second trimester fetuses in the womb. But, to specialists, that is not the choicest of options. Instead they aim to look at adult retinal cells and to draw on its stem cell-like qualities. It would be fitting to conclude that this extraordinary piece of work might well be the torchbearer in eradicating blindness, illuminating many a human life grappling in the dark.