
Rod photoreceptors (in green) within a “mini retina” derived from human iPS cells in the lab©Image courtesy of Johns Hopkins Medicine (PARIS-AFP) – In another step towards reversing degenerative vision loss, scientists said Tuesday they had coaxed stem cells into growing into a tiny, light-sensing retina in a lab dish. The study is an important technical feat in using reprogrammed cells, whose discovery in 2006 has unleashed huge interest, they said. “We have basically created a miniature human retina in a dish that not only has the architectural organisation of the retina but also has the ability to sense light,” said Valeria Canto-Soler of Johns Hopkins University School of Medicine, Baltimore. The work is the latest advance towards the goal of creating transplant cells that reverse damage to the retina, the light-capturing surface on the back of the eyeball. Stem cells are infant cells that develop, or differentiate, into the various tissues of the body. Until 2006, the big focus was on stem cells culled from early-stage embryos, which are highly versatile but also ethically controversial. That changed with the discovery in Japan of so-called human induced pluripotent stem cells (iPS cells), which are adult cells that have been reprogrammed to return to a youthful, pre-differentiated state. The latest research marshalls the iPS into the right architecture for the retina, ordering the complex layers of specific photoreceptor cells which absorb and process light. More work is needed, though, to understand how these cells transmit signals to the brain. Experiments in Read More …